The history of creation, or, The development of the earth and its inhabitants by the action of natural causes : a popular exposition of the doctrine of evolution in general, and of that of Darwin, Goethe and Lamarck in particular

VN'^IN'v ■'■>\^''

1^

■■i'jumti

It

mm\sw

%^'^

i$

"-f^:-

ryM7^/

SX«^^'

.^^»>1

I-Ci

jji

n

o;

Z:

SI

cr

o
o

f-q
o
m

D

■,V ■' ^-r

f»srJm

^^kt

^m^^¥^^r

THE HISTOEY OF CEEATION.

"^^

h

Development of a Calcareous Sponge (Olynthus)

THE

HISTORY OF CREATION :

on THE DEVELOPMENT OF THE EARTH AND ITS
INHABITANTS BY THE ACTION OF NATURAL CAUSES.

A. POPULAR EXPOSITION OP

THE DOCTRINE OF EVOLUTION IN GENERAL, AND OF THAT OF

DARWIN, GOETHE, AND LAMARCK IN PARTICULAR,

FROM THE GERMAN OF

EEN ST HAE CKEL,

PfiOFESSOR IN THE UNIVERSITY OF JE.VxV.

THE TRANSLATION REVISED BY
B. RAT LANKESTER, M,A., FELLOW OF EXETER COLLEGE, OXFORD.

IN TWO VOLUMES.
VOL. I.

NEW YORK:

D. APPLETON AND COMPANY,

I, 3, AND 5 BOND STREET.

I 880.

A sense snbl'me
Of sometliing far more deeply interfused,
Whose dwelling is the light of setting suns.
And the round ocean, and the living air,
And the blue sky, and in the mind of man j
A motion and a spirit that impels
All thinking things, all objects of all thought.
And rolls through all things.

In all things, in all natures, in the starq
Of azure heaven, the nnenduring clouds,
In flower and tree, in every pebbly stone
That paves the brooks, the stationary rocks.
The moving waters and the invisible air.

WORDSWOETH,

CONTENTS OF VOL. L

-VC^

CHAPTER I.

NATURE AND IMPORTANCE OF THE DOCTRINE OP FILIATION,
-cr OR DESCENT.THEORY.

PAGE

General Importance and Essential Nature of the Theory of Descent as
reformed by Darwin, — Its Special Importance to Biology (Zoology
and Botany). — Its Special Importance to the History of the Natural
Development of the Human Race. — The Theory of Descent as the
Non-Miraculous History of Creation. — Idea of Creation. — Know,
ledge and Belief. — History of Creation and History of Development.
— The Connection between the History of Individual and Paloeonto-
logical Development. — The Theory of Purposelessness, or the
Science of Rudimentary Organs. — Useless and Superfluous Ar-
rangements in Organisms. — Contrast between the two entirely
Opposed Views of Nature : the Monistic (mechanical, causal) and
the Dualistic (teleological, vital). — Proof of the former by the
Theory of Descent. — Unity of Organic an4 Inorganic Nature, and
the Identity of the Active Causes in both. — The Importance of
the Theory of Descent to the Monistic Conception of all Nature ... 1

CHAPTER II.

SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT.
HISTORY OP CREATION ACCORDING TO LINN.^US.

The Theory of Descent, or Doctrine of Filiation, as the Monistic Ex-
planation of Organic Natural Phenomena. — Its Comparison with
Newton's Theory of Gravitation. — Limits of Scientific Explanation
and of Human Knowledge in general. — All Knowledge founded
originally on Sensuous Experience, a posteriori. — Transition of d
posteriori knowledge, by inheritance, into a priori knowledge. —
Contrast between the Supernatural Hypotheses of the Creation ac-

V] CONTENTS.

PAGE

coi'ding to Linnaeus, Cuvier, Agassiz, and the Natural Theories of
Development according to Lamarck, Goethe, and Darwin. — Con-
nection of the former with the Monistic (mechanical), of the latter
with the Dualistic Conception of the Universe, — Monism and
Matei-ialism. — Scientific and Moral Materialism. — The History of
Creation according to Moses. — Linnasus as the Founder of the Sys.
teraatic Description of Natui-e and Distinction of Species. — Linnseus'
Classification and Binary Nomenclature. — Meaning of Linnaeus' Idea
of Species. — His History of Creation. — Linnteus' view of the Origin
of Species 24

CHAPTER III.

THE HISTORY OF CREATION ACCORDING TO CUYIER

AND AGASSIZ.

General Theoretical Meaning of the Idea of Species. — Distinction be-
tween the Theoretical and Practical Definition of the Idea of Species.
— Cuvier's Definition of Species. — Merits of Cuvier as the Founder
of Comparative Anatomy. — Distinction of the Four Principal Forms
(types or branches) of the Animal Kingdom, by Cuvier and Bar. —
Cuvier's Services to Palaeontology. — His Hypothesis of the Revo-
lutions of our Globe, and the Epochs of Creation separated by them.
— Unknown Supernatural Causes of the Revolutions, and the sub-
sequent New Creations. — Agassiz's Teleological System of Nature.
— His Conception of the Plan of Creation, and its six Categories
(groups in classification). — Agassiz's Views of the Creation of
Species. — Rude Conception of the Creator as a man -like being
in Agassiz's Hypothesis of Creation. — Its internal Inconsistency
and Contradictions with the important Palaeontological Laws dis-
covered by Agassiz 47

CHAPTER IV.

THEORY OF DEVELOPMENT ACCORDING TO GOETHE

AND OKEN.

Scientific InsnflBciency of all Conceptions of a Creation of Individual
Species — Necessity of the Counter Theories of Development. —
Historical Survey of the most Important Theories of Development.
— Aristotle. — His Doctrine of Spontaneous Generation. — The
Meaning of Nature-philosophy. — Goethe. — His Merits as a
Naturalist. — His Metamorphosis of Plants. — His Vertebral Theory
of the Skull. — His Discovery of the Mid Jawbone in Man. —
Goethe's Interest in the Dispute between Cuvier and Geoffroy

CONTENTS. Vll

PAGE

St. Hilaire. — Goethe's Discovery of the two Organic Formative
Principles, of the Conservative Principle of Specification (by In-
heritance), and of the Progressive Principle of Transformation (by
Adaptation). — Goethe's Views of the Common Descent of all Ver-
tebrate Animals, including Man. — Theory of Development according
to Gottfried Keinhold Treviranus. — His Monistic Conception of
Nature. — Oken. — His Nature-philosophy. — Oken's Theory of
Protoplasm. — Oken's Theory of Infusoria (Cell Theory). — Oken's
Theory of Development ... ... ... ... ... ... 72

CHAPTER V

THEORY OP DEVELOPMENT ACCOEDING TO KANT AND

LAMAECK.

Kant's Dualistic Biology. — His Conception of the Origin of Inorganic
Nature by Mechanical Causes, of Organic Natui'e by Causes acting
for a Definite Purpose. — Contradiction of this Conception with his
leaning towards the Theory of Descent. — Kant's Genealogical
Theory of Development. — Its Limitation by his Teleology. — Com-
parison of Genealogical Biology with Comparative Philology. —
Views in favour of the Theory of Descent entertained by Leopold
Buch, Bar, Schleiden, Unger, Schaafhausen, Victor Cams, Biichner.
— French Nature -philosophy. — Lamarck's Philosophie Zoologique. —
Lamarck's Monistic (mechanical) System of Nature. — His Views
of the Inter-action of the two Organic Formative Tendencies of
Inheritance and Adaptation. — Lamarck's Conception of Man's
Development from Ape-like Mammals. — Geoffrey St. Hilaire's,
Naudin's, and Lecoq's Defence of the Theory of Descent. — English
Nature -philosophy. — Views in favour of the Theory of Descent
entertained by Erasmus Darwin, W. Herbert, Grant, Freke, Herbert
Spencer, Hooker, Huxley. — The Double Merit of Charles Darwin ... 100

CHAPTER VI.

THEOEY OF DEVELOPMENT ACCOEDING TO LYELL

AND DAEWIN.

Charles Lyell's Principles of Geology. — His Natural History of the
Earth's Development. — Origin of the Greatest Effects thi'ough the
Multiphcation of the Smallest Causes. — Unlimited Extent of Geo-
logical Periods. — Lyell's Eefutationof Cuvier's History of Creation.
— The Establishment of the Uninterrupted Connection of Historical
Development by Lyell and Darwin. — Biographical Notice of Charles
Dai-win. — His Scientific Works. — Jlis Theory of Coral Eeefs. — De-

VIU CONTENTS.

PAGE

velopment of the Theory of Selection. — A Letter of Darwin's. —
The Contemporaneous Appearance of Darwin's and Alfred Wallace's
Theory of Selection. — Darwin's Study of Domestic Animals and
Cultivated Plants. — Andreas Wagner's Notions as to the Special
Creation of Cultivated Organisms for the good of Man. — The Tree
of Knowledge in Paradise. — Comparison between Wild and Culti-
vated Organisms. — Darwin's Study of Domestic Pigeons. — Import-
ance of Pigeon Breeding. — Common Descent of all Eaces of
'jtigeons ••• ••• ••• ••• ..( ,,, ,,t ,,, ,,, i.^0

CHAPTER VII.

THE THEORY OF SELECTION (DARWINISM).

Darwinism (Theory of Selection) and Lamarckism (Theoiy of Descent).
— The Process of Artificial Breeding. — Selection of the Different
Individuals for After-breeding. — The Active Causes of Transmuta-
tion.— Change connected with Food and Transmission by Inheritance
connected with Propagation. — Mechanical Nature of these Two
Physiological Functions. — The Process of Natural Breeding :
Selection in the Struggle for Existence. — Malthus' Theory of
Population. — The Proportion between the Numbers of Potential
and Actual Individuals of every Species of Organisms. — General
Straggle for Existence, or Competition to attain the Necessaries of
Life. — Transforming Force of the Struggle for Existence. — Com-
parison of Natural and Artificial Breeding — Selection in the Life of
Man. — Military and Medical Selection ... ... ... ... 149

CHAPTER YIII.

TRANSMISSION BY INHERITANCE AND PROPAGATION.

Universality of Inheritance and Transmission by Inheritance. — Special
Evidences of the same. — Human Beings with four, six, or seven
Fingers and Toes. — Porcupine Men. — Transmission of Diseases,
especially Diseases of the Mind. — Original Sin. — Hereditary
Monarchies. — Hereditary Aristocracy. — Hereditary Talents and
Mental Qualities. — Material Causes of Transmission by Inheritance.
— Connection between Transmission by Inheritance and Propaga-
tion. — Spontaneous Genei-ation and Propagation. — Nonsexual or
Monogonous Propagation. — Propagation by Self -Division. — Monera
and Amoeba. — Propagation by the formation of Buds, by the for-
mation of Germ-Buds, by the foi-mation of Germ-Cells. — Sexual or
Amphigonous Propagation. — Formation of Hermaphrodites. — Dis-
tinction of Sexes, or Gonochorism. — Virginal Breeding, or Parthe-

CONTENTS. IX

PAGE

nogenesis. — Material Transmission of Peculiarities of both Parents
to the Child by Sexual Propagation. — Difference between Trans-
mission by Inheritance in Sexual and in Asexual Propagation ... 175

CHAPTER IX.

LAWS OF TRANSMISSION BY INHERITANCE.
ADAPTATION AND NUTRITION.

Distinction between Conservative and Pr-ogressive Transmission by In-
heritance.— Laws of Conservative Transmission : Transmission of
Inherited Characters. — Uninten-upted or Continuous Transmission.
— Interrupted or Latent Transmission. — Alternation of Generations.
" — Relapse. — Degeneracy. — Sexual Transmission. — Secondary
Sexual Characters. — Mixed or Amphigonoua Transmission. —
Hybrids. — Abridged or Simplified Transmission. — Laws of Pro-
gressive Inheritance : Transmission of Acquired Characters. —
Adapted or Acquired Transmission. — Fixed or Established Trans-
mission. — Homochronous Transmission (Identity in Epoch) . —
nomotopic Transmission (Identity in Part). — Adaptation and
Mutability. — Connection between Adaptation and Nutrition. — Dis-
tinction between Indirect and Direct Adaptation ,., ,,. ... 203

CHAPTER X.
LAWS OP ADAPTATION

Laws of Indirect or Potential Adaptation. — Individual Adaptation. —
Monstrous or Sudden Adaptation. — Sexual Adaptation. — Laws of
Direct or Actual Adaptation. — Universal Adaptation. — Cumulative
Adaptation. — Cumulative Influence of External Conditions of Ex-
istence and Cumulative Counter-Influence of the Organism. — Free
Will. — Use and Non-use of Organs. — Practice and Habit. — Cor-
relative Adaptation. — Correlation of Development. — Correlation of
Organs. — Explanation of Indirect or Potential Adaptation by the
Correlation of the Sexual Organs and of the other parts of the
Body. — Divergent Adaptation. — Unlimited or Infinite Adaptation... 227

r

CHAPTER XI.

NATURAL SELECTION BY THE STRUGGLE FOR EXISTENCE.
DIVISION OF LABOUR AND PROGRESS.

Interaction of the two Organic Formative Causes, Inheritance and
Adaptation. — Natural and Artificial Selection. — Struggle for Ex-
istence, or Competition for the Necessaries of Life. — Disproportion

CONTENTS.

PACE

between the Number of Possible or Potential, and tlie Number of
Keal or Actual Individuals. — Complicated Correlations of all Neigh-
bouring Organisms. — Mode of Action in NatmTil Selection. — Homo-
chromic Selection as the Cause of Sympathetic Colourings. —
Sexual Selection as the Cause of the Secondary Sexual Characters.
— Law of Separation or Division of Labour (Polymorphism, Differ-
entiation, Divergence of Chai-acters) . — Transition of Varieties into
Species. — Idea of Species. — Hybridism. — Law of Progress or Per-
fecting (Progressus, Teleosis) ... ... ... ... ... ... 252

CHAPTER XII.

LAWS OF DEVELOPMENT OF ORGANIC TRIBES AND OF
INDIVIDUALS. PHYLOGENY AND ONTOGENY.

Laws of the Development of Mankind : Differentiation and Perfecting.
— Mechanical Cause of these two Fundamental Laws. — Progress
without Differentiation, and Differentiation without Progress. — •
Origin of Rudimentary Organs by Non-use and Discontinuance of
Habit. — Ontogenesis, or Individual Development of Organisms. —
Its General Importance. — Ontogeny, or the Individual History of
Development of Vertebrate Animals, including Man. — The Fructi-
fication of the Egg. — Formation of the Three Germ Layers.—
History of the Development of the Central Nervous System, of the
Extremities, of the Branchial Arches, and of the Tail of Vertebrate
Animals. — Causal Connection and Parallelism of Ontogenesis and
Phylogenesis, that is, of the Development of Individuals and Tribes.
— Causal Connection of the Parallelism of Phylogenesis and of
Systematic Development. — Parallelism of the three Organic Series
of Development 280

CHAPTER XIII.

THEORY OF THE DEVELOPMENT OF THE UNIVERSE AND OF
THE EARTH. SPONTANEOUS GENERATION. THE CARBON
THEORY. THE PLASTID THEORY.

History of the Development of the Earth. — Kant's Theory of the De-
velopment of the Universe, or the Cosmological Gas Theory. —
Development of Suns, Planets, and Moons. — First Origin of Water.
— Comparison of Organisms and Anorgana. — Organic and Inorganic
Substances. — Degrees of Density, or Conditions of Aggregation. — -
Albuminous Combinations of Carbon. — Organic and Inorganic
Forms. — Crystals and Formless Organisms without Organs. —

CONTENTS. XI

PAGE

Stereometrical Fundamental Forms of Crystals and of Organisms. —
Organic and Inorganic Forces. — Yital Force. — Growth and Adapta-
tion in Crystals and in Organisms, — Formative Tendencies of
Crystals. — Unity of Organic and Inorganic Nature. — Spontaneous
Generation, or Archigony. — Autogony and Plasmogony. — Origin of
Monera by Spontaneous Generation. — Origin of Cells from Monera.
— The Cell Theory. — The Plastid Theory. — Plastids, or Structm^al-
Units. — Cytods and Cells. — Four Different Kinds of Plastids ... 316

CHAPTER Xiy.

MIGEATION AND DISTRIBUTION OF ORGANISMS. CHOROLOGY
AND THE ICE-PERIOD OF THE EARTH.

Chorological Facts and Causes. — Origin of most Species in one Single
Locality. — "Centres of Creation." — Distribution by Migration. —
Active and Passive Migrations of Animals and Plants. — Means of
Transport. — Transport of Germs by Water and by Wind. — Con-
tinual Change of the Area of Distribution by Elevations and
Depressions of the Groimd. — Chorological Importance of Geological
Processes. — Influence of the Change of Climate. — Ice or Glacial
Period. — Its Importance to Chorology. — Importance of Migrations
for the Origin of New Species. — Isolation of Colonists. — Wagner's
Law of Migration. — Connection between the Theory of Migration
and the Theory of Selection. — Agreement of its Results with the
Theoiy of Descent «•• ••• ..* ... 350

LIST OF ILLTJSTEATIOlSrS.

-*o^

PLATES.

Development of a Calcareotis Sponge (Olynthus) ...

I. — Life History of a Simplest Organism ...

II., III. — Germs or Embryos of Four Vertebrates ...

TAGS

... Frontispiece

To face page 184

„ 306

FIGUEES.
1. — Propagation of Moneron ...
2. — Propagation of Amoeba ...
3. — Egg of Mammal ...
4. — First Development of Mammal's Egg
5. — The Hmnan Egg Enlarged
6. — Development of Mammal's Egg
7. — Embryo of a Mammal or Bird ...

186

188

189

190

297

299

S04.

AUTHOR'S PEEFACE TO THE ENGLISH EDITION,

-»♦*-

I AM desirous of prefacing the English edition of the
" History of Creation " with a few remarks which may serve
to explain the origin and object of this book. In the year
1866 I published, under the title " Generelle Morphologic,"
a somewhat comprehensive work, which constituted the first
attempt to apply the general doctrine of development to the
whole range of organic morphology (Anatomy and Biogenesis),
and thus to make use of the vast march onwards which the
genius of Charles Darwin has eflected in all biological
science by his reform of the Descent Theory and its esta-
blishment through the doctrine of selection. At the same
time, in the " Generelle Morphologic," the first attempt was
made to introduce the Descent Theory into the systematic
classification of animals and plants, and to found a " natural
system " on the basis of genealogy ; that is, to construct
hj^pothetical pedigrees for the various species of organisms.

The " Generelle Morphologic " found but few readers, for
which the voluminous and unpopular style of treatment, and
its too extensive Greek terminology, may be chiefly to blame.
But a proportionately large measure of approval has met

XIV PREFACE.

the " Naturliche Schopfimgsgeschiclite '* in Germany. This
book took its origin in the shorthand notes of a course ot
lectures which treated, before a mixed audience and in
a popular form, the most important topics discussed in the
" Generelle Morphologie." The notes were subsequently
revised, and received considerable additions. The book
appeared first in 1868, its fourth edition in 1873, and has
been translated into several languages. I hope that it may
also find sympathy in the fatherland of Darwin, the more so
since it contains special morphological evidence in favour of
many of the important doctrines with which this greatest
naturalist of our century has enriched science. Proud as
England may be to be called the fatherland of Newton, who,
with his law of gravitation, brought inorganic nature under
the dominion of natural laws of cause and effect, yet may
she with even greater pride reckon Charles Darwin among
her sons — he who solved the yet harder problem of bring-
ing the complicated phenomena of organic nature under the
sway of the same natural laws.

The reproach which is now oftenest made against the
Descent Theory is that it is not securely founded, not suffi-
ciently proven. Not only its distinct opponents maintain that
there is a want of satisfactory proofs, but even faint-hearted
and wavering adherents declare that Darwin's hypothesis is
still wanting fundamental proof. Neither the former nor the
latter estimate rightly the immeasurable weight which the
great series of phenomena of comparative anatomy and onto-
geny, palaeontology and taxonomy, chorology and cecology,
cast into the scale in favour of the doctrine of filiation.
Darwin's Theory of Selection, which completely explains the
origin of species through the combined action of Inheritance

PREFACE. XV

and Adaptation in the struggle for existence, also appears to
these persons not sufficient. They demand, over and above,
that the descent of species from common ancestral forms
shall be proved in a particular case ; that, in contradistinc-
tion to the synthetic proofs adduced for the Descent Theory,
the analytic proof of the genealogical continuity of the
several species shall be brought forward.

This " analytical solution of the problem of the origin of
species " I have myself endeavoured to afford in my recently
published " Monograph of the Calcareous Sponges." For five
consecutive years I have investigated this small but highly
instructive group of animals in all its forms in the most
careful manner, and I venture to maintain that the mono-
graph, which is the result of those studies, is the most
complete and accurate morphological analysis of an entire
organic group which has up to this time been made.
Provided with the whole of the material for study as yet
brought together, and assisted by numerous contributions
from all parts of the world, I was able to work over the
whole group of organic forms known as the Calcareous
Sponges in that greatest possible degree of fulness which
appeared indispensable for the proof of the common origin
of its species. This particular animal group is especially
fitted for the analytical solution of the species problem,
because it presents exceedingly simple conditions of organ-
ization, because in it the morphological conditions possess a
greatly superior, and the physiological conditions an inferior,
import, and because all species of Calcispongise are remark-
able for the fluidity and plasticity of their form. With a
view to these facts, I made two journeys to the sea-coast
(1869 to Norway, 1871 to Dalmatia), in order to study as

XVI PREFACE.

large a number of individuals as possible in their natural
circumstances, and to collect specimens for comparison. Of
many species, I compared several hundred individuals in the
most careful way. I examined with the microscope and
measured in the most accurate manner the details of form of
all the species. As the final result of these exhaustive
and almost endless examinations and measurements it
appeared that "good species," in the ordinary dogmatic
sense of the systematists, have no existence at all among
the Calcareous Sponges ; that the most different forms are
connected one with another by numberless gradational
transition forms ; and that all the different species of Calca-
reous Sponges are derived from a single exceedingly simple
ancestral form, the Olynthus. A drawing of the Olynthus
and its earliest stages of development (observe especially the
highly important Gastrula) is given in the frontispiece of
the present edition. Illustrations of the various structural
details which establish the derivation of all Calcareous
Sponges from the Olynthus, are given in the atlas of
sixty plates which accompanies my monograph of the
group. In the gastrula, moreover, is now also found the
common ancestral form from which all the tribes of animals
(the lowest group, that of the protozoa, alone being excepted)
can without difficulty be derived. It is one of the most
ancient and important ancestors of the human race !

If we take for the limitation of genus and species an average
standard, derived from the actual practice of systematists, and
apply this to the whole of the Calcareous Sponges at present
known, we can distinguish about twenty-one genera, with one
hundred and eleven species (as I have done in the second
volume of the Monograph). I have, however, shown that we

PEEFACE. XVll

may draw up, in addition to this, another systematic arrange-
ment (more nearly agreeing with the arrangement of the Calci-
spongise hitherto in vogue) which gives thirty-nine genera
and two hundred and eighty-nine species. A systematist
who gives a more limited extension to the " ideal species "
might arrange the same series of forms in forty-three genera
and three hundred and eighty-one species, or even in one
hundred and thirteen genera and five hundred and ninety
species ; another systematist, on the other hand, who takes a
wider limit for the abstract " species," would use in arrang-
ing the same series of forms only three genera, with twenty-
one species, or might even satisfy himself with one genus
and seven species. The delimitation of species and genera
appears to be so arbitrary a matter, on account of endless
varieties and transitional forms in this group, that their
number is entirely left to the subjective taste of the indi-
vidual systematist. In truth, from the point of view of the
theory of descent, it appears altogether an unimportant ques-
tion as to whether we give a wider or a narrower signifi-
cation to allied groups of forms — whether we choose, that is
to say, to call them genera or species, varieties or sub-species.
The main fact remains undeniable, viz., the common origin
of all the species from one ancestral form. The many-
shaped Calcareous Sponges furnish, in the very remarkable
conditions of their varieties of aggregation (metrocormy), a
body of evidence in favour of this view which could hardly
be more convincing. Not unfrequently the case occurs of
several different forms growing out from a single " stock "
or " cormus " — forms which until now have been regarded
b}^ systematists, not only as belonging to different species,
but even to different genera. Fig. 10 in the frontispiece

XVlll PREFACE.

represents such a composite stock. This solid and tangible
piece of evidence in favour of the common descent of
different species ought, one would think, to satisfy the most
determined sceptic !

In point of fact, I have a right to expect of my opponents
that they shall carefully consider the " exact empirical proof"
here brought forward for them, as they have so eagerly
demanded. The opponents of the doctrine of filiation, who
have too little power of weighing evidence, or possess too
little knowledge to appreciate the overpowering weight of
proof afforded by the synthetical argument (comparative
anatomy, ontogeny, taxonomy, etc.), may yet be able to
follow me along the path of analytical proof, and attempt to
upset the conclusion as to the common origin of all species
of all Calcareous Sponges which I have given in my Mono-
graph. I must, however, repeat that this conclusion is
based on the most minute investigation of an extraordinarily
rich mass of material, — that it is securely established by
thousands of the most careful microscopical observations,
measurements, and comparisons of every single part, and
that thousands of collected microscopic preparations render,
at any moment, the most searching criticism of my results
confirmatory of their correctness. One may hope, then, that
opponents will endeavour to confront me on the ground of
this "exact empiricism," instead of trying to damn my
"nature-philosophical speculations." One may hope that
they will endeavour to bring forward some evidence to
show that the latter do not follow as the legitimate conse-
quences of the former. May they, however, spare me the
empty — though by even respectable naturalists oft-repeated
— phrase, that the monistic nature-philosophy, as expounded

PEEFACE. XIX

in tlie "General Morphology," and in the "History of
Creation," is wanting in actual proofs. The proofs are
there. Of course those who turn their eyes away from
them will not see them. Precisely that "exact" form of
analytical proof which the opponents of the descent theory
demand is to be found, by anybody who wishes to find it,
in the " Monograph of the Calcareous Sponges."

Eknst Heinrich Haeckel.

Jena, June 2Wh, 1873.

NOTE

-♦o«-

Feeling sure that such a book as Professor Haeckel's
" Schopfungsgeschichte " would do a great deal of good, if
placed in the hands of the English reading public, and of
commencing students of Natural History, I gladly under-
took to revise for the publishers the present translation,
which was made by a young lady. I have not attempted
to escape a difficulty by ignoring the German names made
use of by Professor Haeckel for classes, orders, and genera,
but have adopted English equivalents. I do not submit
these names as a maturely considered English nomenclature,
they appear here simply as necessary parts of a close ren-
dering of the German work. I do, however, hold that some
such series of English terms is both possible and useful, and
do not doubt — in spite of the pretended hostility of the
genius of our language, and the curious sentimental objec-
tion that English names are unscientific — that we shall
before long make use of plain English in speaking of the
various groups of plants and animals — much to the gain of
the larger public, and without detriment to the latinized
nomenclature established for the purposes of the professional
student.

E. K. L.

Oxfordf October, 1874.

THE HISTOET OF CEEATION.

-♦o*-

CHAPTER L

NATURE AND IMPORTANCE OF THE DOCTRINE OF
FILIATION, OR DESCENT-THEORY.

General Importance and Essential Nature of tlie Theory of Descent as re.
formed by Darwin. — Its Special Importance to Biology (Zoology and
Botany). — Its Special Importance to the History of the Natural Develop-
ment of the Human Eace. — The Theory of Descent as the Non-Miraculous
History of Creation. — Idea of Creation. — Knowledge and Belief. — His-
tory of Creation and History of Development. — The Connection between
the History of Individual and Palseontological Development. — The
Theory of Purposelessness, or the Science of Rudimentary Organs. —
Useless and Superfluous Arrangements in Organisms. — Contrast between
the two entirely opposed Views of Nature : the Monistic (mechanical,
causal) and the Dualistic (teleological, vital). — Proof of the former by
the Theory of Descent. — Unity of Organic and Inorganic Nature, and
the Identity of the Active Causes in both. — The Importance of the
Theory of Descent to the Monistic Conception of all Nature.

The intellectual movement to which the impulse was given,
thirteen years ago, by the English naturalist, Charles
Darwin, in his celebrated work, " On the Origin of
Species,"^ has, within this short period, assumed dimen-
sions which cannot but excite the most universal interest. It
is true the scientific theory set forth in that work, which is
commonly called briefly Darwinism, is only a small fragment
of a far more comprehensive doctrine — a part of the universal

2 THE HISTOHY OF CREATION.

Theory of Development, wliicli embraces in its vast range
the whole domain of human knowleclofe.

But the manner in which Darwin has firmly established
the latter by the former is so convincing, and the direction
which has been given by the unavoidable conclusions of
that theory to all our views of the universe, must appear to
every thinking man of such deep significance, that its
general importance cannot be over estimated. There is no
doubt that this immense extension of our intellectual
horizon must be looked upon as by far the most important,
and rich in results, among all the numerous and grand
advances which natural science has made in our day.

When our century, with justice, is called the age of
natural science, when we look with pride upon the im-
mensely important progress made in all its branches, we
are generally in the habit of thinking more of immediate
practical results, and less of the extension of our general
knowledge of nature. We call to mind the complete reform,
so infinitely rich in consequences to human intercourse,
which has been effected by the development of machinery,
by railways, steamships, telegraphs, and other inventions
of physics. Or we think of the enormous influence which
chemistry has brought to bear upon medicine, agriculture,
and upon all arts and trades.

But "much as we may value this influence of modem
science upon practical life, still it must, estimated from a
hio-her and more general point of view, stand most assuredly
below the enormous influence which the theoretical progress
of modern science will have on the entire range of human
knowledge, on our conception of the universe, and on the
perfecting of man's culture.

IMPORTANCE OF DARWINISM. 3

Think of the immense revolutions in all our theoretical
views which we owe to the general application of the
microscope. Think of the cell theory, which explains the
apparent unity of the human organism as the combined
result of the union of a mass of elementary vital units. Or
consider the immense extension of our theoretical horizon
which we owe to spectral analysis and to the mechanical
theory of heat. But among all these wonderful theoretical
advances, the theory wrought out by Darwin occupies by
far the highest rank.

Every one of my readers has heard of the name of Dar-
win. But most persons have probably only an imperfect
idea of the real value of his theory. If a reader estimates
as of equal value all that has been written upon Darwin's
memorable work since its appearance, the value of the
theory will appear very doubtful to him, supposing that
he has not been engaged in the organic natural sciences,
and has not penetrated into the inner secrets of zoology
and botany. The criticisms of it are so full of contradic-
tions, and for the most part so defective, that we ought not
to be at all astonished that even now, after the lapse of
thirteen years since the appearance of Darwin's work, it has
not gained half that importance which is justly due to it,
and which sooner or later it certainly will attain.

Most of the innumerable writings which have been pub-
lished during these years, both for and against Darwinism,
are the productions of persons who are entirely wanting in
the necessary amount of biological, and especially of zoolo-
gical, knowledge. Although almost all of the more celebrated
naturalists of the present day are adherents of the theory,
yet only a few of them have endeavoured to procure its

4 THE HISTOEY OF CREATION.

acceptance and recognition in larger circles. Hence the
odd contradictions and the strange opinions which may still
be heard everywhere about Darwinism. This is the reason
which induces me to make Darwin's theory, and those further
doctrines which are connected with it, the subject of these
pages, which, I hope, will be generally intelligible. I hold
it to be the duty of naturalists, not merely to meditate upon
improvements and discoveries in the narrow circle to which
their speciality confines them, not merely to pore over their
one study with love and care, but also to seek to make the
important general results of it fruitful to the mass, and to
assist in spreading the knowledge of physical science among
the people. The highest triumph of the human mind, the
true knowledge of the most general laws of nature, ought
not to remain the private possession of a privileged class of
savans, but ought to become the common property of all
mankind.

The theory which, through Darwin, has been placed at
the head of all our knowledge of nature, is usually called the
Doctrine of Filiation, or the Theory of Descent. Others term
it the Transmutation Theory. Both designations are correct.
For this doctrine affirms, that all organisons (viz. all species
of animals, all species of plants, which have ever existed or
still exist on the earth) are derived from one single, or from
a few simple original forons, and that they have developed
theonselves from these in the natural course of a gradual
change. Although this theory of development had already
been brought forward and defended by several great natm-al-
ists, and especially by Lamarck and Goethe, in the beginning
of our centiu-y, still it was through Darwin, thirteen years
ago, that it received its complete demonstration and causal

OEGANA AND ANOEGAXA. 5

foundation ; and this is the reason why now it is commonly
and exclusively (though not quite correctly) designated as
Darwin's Theory,

The great and really inestimable value of the Theory of
Descent appears in a different light, accordingly as we
merely consider its more immediate connection with organic
natural science, or its larger influence upon the whole range
of man's knowledge of the universe. Organic natural
science, or Biology, which as Zoology treats of animals, as
Botany of plants, is completely reformed and founded anew
by the Theory of Descent. For by this theory we are made
acquainted with the active causes of organic forms, while up
to the present time Zoology and Botany have simply been
occupied with the facts of these forms. We may therefore
also term the theory of descent a onechanical explanation of
organic forms, or the science of the true causes of Organic
Nature.

As I cannot take for granted that my readers are all

familiar with the terms " organic and inorganic nature,"

and as the contrast of both these natural bodies will, in

future, occupy much of our attention, I must say a few

words in explanation of them. We designate as Organisms,

or Organic bodies, all living creatures or animated bodies;

therefore all plants and animals, man included ; for in them

we can almost always prove a combination of various parts

(instruments or organs) which work together for the purpose

of producing the phenomena of life. Such a combination

we do not find in Anorgana, or inorganic natural bodies —

the so-called dead or inanimate bodies, such as minerals or

stones, water, the atmospheric air, etc. Organisms always

contain albuminous combinations of carbon in a semi-fluid
2

6 THE HISTORY OF CREATION.

condition of aggregation, which are always wanting in the
Anorgana. Upon this important distinction rests the divi-
sion of all natural history into two great and principal parts
— Biology, or the science of Organisms (Zoology and Botany),
and Anorganology, or the science of Anorgana (Mineralogy,
Geology, Meteorology, etc.).

The great value of the Theory of Descent in regard to
Biology consists, as I have already remarked, in its explain-
ing to ns the origin of organic forms in a mechanical way,
and pointing out their active causes. But however highly
and justly this service of the Theory of Descent may be
valued, yet it is almost eclipsed by the immense importance
which a single necessary inference from it claims for itself
alone. This necessary and unavoidable inference is the
theory of the animal descent of the human race.

The determination of the position of man in nature, and
of his relations to the totality of things — this question of all
questions for mankind, as Huxley justly calls it — ^is finally
solved by the knowledge that man is descended from
animals. In consequence of Darwin's reformed Theory of
Descent, we are now in a position to establish scientifically
the groundwork of a non-miixiculous history of the de-
velopment of the human race. All those who have defended
Darwin's theory, as well as all its thoughtful opponents, have
acknowledged that, as a matter of necessity, it follows from
his theory that the human race, in the fii^st place, must be
traced to ape-like mammals, and further back to the lower
vertebrate animals.

It is true Darwin himself did not express at first this
most important of all the inferences from his theory. In
nis work, " On the Origin of Species," not a word is found

OEIGIN OF MAN. 7

about the animal descent of man. The courageous but
cautious naturalist was at that time purposely silent on the
subject, for he anticipated that this most important of all
the conclusions of the Theory of Descent was at the same
time the greatest obstacle to its being generally accepted
and acknowledged. Certain it is that Darwin's book would
have created, from the beginning, even much more opposi-
tion and offence, if this most important inference had at
once been clearly expressed. It was not till twelve years
later, in his work on " The Descent of Man, and Selection
in Eelation to Sex," that Darwin openly acknowledged that
far-reaching conclusion, and expressly declared his entire
agreement with those naturalists who had, in the mean-
time, themselves formed that conclusion. Manifestly the
effect of this conclusion is immense, and no science will be
able to escape from the consequences. Anthropology, or the
science of man, and consequently all philosophy, are thereby
thoroughly reformed in all their various branches.

It will be a later task in these pages to discuss this
special point. I shall not treat of the theory of the animal
descent of man till I have spoken of Darwin's theory, and
its general foundation and importance. To express it in
one word, that most important, but (to most men) at first
repulsive, conclusion is nothing more than a special deduc-
tion, which we must draw from the general inductive law
of the descent theory (now firmly established), according to
the stern commands of inexorable logic.

Perhaps nothing will make the full meaning of the theory
of descent clearer than calling it " the non-miraculous
history of creation." I have therefore chosen that name
for this work. It is, however, correct only in a certain

8 THE HISTORY OF CREATION.

sense, and it must be borne in mind that, strictly speaking,
the expression "non-miraculous history of creation" contains
a " contradictio in adjecto."

In order to understand this, let us for a moment examine
somewhat more closely what we understand by creation.
If we understand the creation to mean the coming into
existence of a body by a creative power or force, we may
then either think of the coming into existence of its sub-
stance (corporeal matter), or of the coming into existence of
its form (the corporeal form).

Creation in the former sense, as the coming into existence
of matter, does not concern us here at all. This process, if
indeed it ever took place, is completely beyond human com-
prehension, and can therefore never become a subject of
scientific inquiry. Natural science teaches that matter is
eternal and imperishable, for experience has never shown us
that even the smallest particle of matter has come into
existence or passed away. Where a natural body seems to
disappear, as for example by burning, decaying, evaporation,
etc., it merely changes its form, its physical composition or
chemical combination. In like manner the coming into
existence of a natural body, for example, of a crystal, a
fungus, an infusorium, depends merely upon the different
particles, which had before existed in a certain form or com-
bination, assuming a new form or combination in conse-
quence of changed conditions of existence. But never yet
has an instance been observed of even the smallest particle
of matter having vanished, or even of an atom being added
to the already existing mass. Hence a naturalist can no
more imagine the coming into existence of matter, than he
can imagine its disappearance, and he therefore looks upon

SCIENCE AND FAITH. 9

the existing quantity of matter in the universe as a given
fact. If any person feels the necessity of conceiving the
coming into existence of this matter as the work of a super-
natural creative power, of the creative force of something
outside of matter, we have nothing to say against it. But
we must remark, that thereby not even the smallest advan-
tage is gained for a scientific knowledge of nature. Such a
conception of an immaterial force, which at the first creates
matter, is an article of faith which has nothing whatever
to do with human science. Where faith com')nences, science
ends. Both these arts of the human mind must be strictly
kept apart from each other. Faith has its origin in the
poetic imagination ; knowledge, on the other hand, originates
in the reasoning intelligence of man. Science has to pluck
the blessed fruits from the tree of knowledge, unconcerned
whether these conquests trench upon the poetical imagin-
ings of faith or not.

If, therefore, science makes the " history of creation " its
highest, most difficult, and most comprehensive problem, it
must accept as its idea of creation the second explanation
of the word, viz. the coming into being of the form of
natural bodies. In this way geology, which tries to in-
vestigate the origin of the inorganic surface of the earth as
it now appears, and the manifold historical changes in the
form of the solid crust of the earth, may be called the
history of the creation of the earth. In like manner, the
history of the development of animals and plants, which
investigates the origin of living forms, and the manifold
historical changes in animal and vegetable forms, may be
termed the history of the creation of organisms. As, how-
ever, in the idea of creation, although used in this sense, the

lO THE HISTORY OF CEEATLON.

unscientific idea of a creator existing outside of matter, and
changing it, may easily creep in, it will perhaps be better in
future to substitute for it the more accurate term, develop-
vient

The great value which the History of Development pos-
sesses for the scientific understanding of animal and vege-
table forms, has now been generally acknowledged for many
years, and without it it would be impossible to make any
sure progress in organic morphology, or the theory of forms.
But by the history of development, only one part of this
science has generally been understood, namely, that of
organic individuals, usually called Embryology, but more
correctly and comprehensively, Ontogeny. But, besides this,
there is another history of development of organic species,
genera, and tribes (phyla), which has the most important
relations to the formet.

The subject of this is furnished to us by the science of
petrifactions, or palaeontology, which shows us that each
tribe of animals and plants, during different periods of the
earth's history, has been represented by a series of entirely
different genera and species. Thus, for example, the tribe
of vertebrated animals was represented by classes of fish,
amphibious animals, reptiles, birds, and mammals, and each
of these groups, at different periods, by quite different kinds.
This palseontological history of the development of organ-
isms, which we may term Phylogeny, stands in the most
important and remarkable relation to the other branch of
oi^ganic history of development, I mean that of individuals,
or Ontogeny. On the whole, the one runs parallel to the
other. In fact, the history of individual development, or
Ontogeny, is a short and quick recapitulation of palaeonto-

BIOLOGY EEFOKMED. II

logical development, or Phylogeny, dependent on the laws
of Inheritance and Adaptation.

As I shall have, later, to explain this most interesting and
important coincidence more fully, I shall not dwell further
upon it here, and merely call attention to the fact that it
can only be explained and its causes understood by the
Theory of Descent, while without that theory it remains
completely incomprehensible and inexplicable. The Theory
of Descent in the same way shows us why individual animals
and plants must develop at all, and why they do not come
into life at once in a perfect and developed state. No super-
natural history of creation can in any way explain to us
the great mystery of organic development. To this most
weighty question, as well as to all other biological ques-
tions, the Theory of Descent gives us perfectly satisfactory
answers — and always answers which refer to purely me-
chanical causes, and point to purely physico-chemical forces
as the causes of phenomena which we were formerly accus-
tomed to ascribe to the direct action of supernatural,
creative forces. Hence, by our theory the mystic veil of
the miraculous and supernatural, which has hitherto been
allowed to hide the complicated phenomena of this branch
of natural knowledge, is removed. All the departments of
Botany and Zoology, and especially the most important por-
tion of the latter, Anthropology, become reasonable. The
dimming mirage of mythological fiction can no longer
exist in the clear sunlight of scientific knowledge.

Of special interest among general biological phenomena
are those which are quite irreconcilable with the usual
supposition, that every organism is the product of a creative
power, acting for a definite object. Nothing in this respect

12 THE HISTOEY OF CREATION.

caused the earlier naturalists greater difficulty tlian tlie
explanation of the so-called " rudimentary organs" — those
parts in animal and vegetable bodies which really have no
function, which have no physiological importance, and yet
exist in form. These parts deserve the most careful atten-
tion, aithouo^h most unscientific men know little or nothino^
about them. Almost every organism, almost every animal
and plant possesses, besides the obviously useful arrange-
ments of its organization, other arrangements the purpose
of which it is utterly impossible to make out.

Examples of this are found everywhere. In the embryos
of many ruminating animals — among others, in our common
cattle — fore-teeth, or incisors, are placed in the mid-bone of
the upper jaw, which never fully develop, and therefore
serve no purpose. The embryos of many whales — ^which
afterwards possess the well-known whalebone instead of
teeth, yet have before they are born, and while they take no
nourishment, teeth in their jaws, which set of teeth never
comes into use. Moreover, most of the higher animals pos-
sess muscles which are never employed ; even man has such
rudimentary muscles. Most of us are incapable of moving
our ears as we wish, although the muscles for this move-
ment exist, and although individual persons who have
taken the trouble to exercise these muscles do succeed in
moving their ears. It is still possible, by special exercise,
by the persevering influence of the will upon the nervous
system, to reanimate the almost extinct activity in the
existing but imperfect organs, which are on the road to
complete disappearance. On the other hand, we can no
longer do this with another set of small rudimentary
muscles, which still exist in the cartilage of the outer ear.

RUDIMENTARY ORGANS. 13

but wliicli are always perfectly inactive. Our long-eared
ancestors of the tertiary period — apes, semi-apes, and
pouched animals, like most other mammals, moved their
large ear-flaps freely and actively; their muscles were much
more strongly developed and of great importance. In a
similar way, many varieties of dogs and rabbits, under the
influence of civilized life, have left off " pricking up " their
ears, and thereby have acquired imperfect amricular muscles
and loose-hanging ears, although their wild ancestors moved
their stiff" ears in many ways.

Man has also these rudimentary organs on other parts of
his body ; they are of no importance to life, and never per-
form any function. One of the most remarkable, although
the smallest organ of this kind, is the little crescent-like fold,
the so-called "plica semilunaris," which we have in the
inner corner of the eye, near the root of the nose. This in-
significant fold of skin, which is quite useless to our eye,
is the imperfect remnant of a third inner eyelid which,
besides the upper and under eyelid, is highly developed in
other mammals, and in birds and reptiles. Even our very
remote ancestors of the Silurian period, the Primitive Fishes,
seem to have possessed this third eyelid, the so-called nicti-
tating membrane. For many of their nearest kin, who still
exist in our day but little changed in form, viz. many
sharks, possess a very strong nictitating membrane, which
they can draw right across the whole eyeball, from the inner
corner of the eye.

Eyes which do not see form the most striking example of
rudimentary organs. These are found in very many animals,
which live in the dark, as in caves or underground. Their
eyes often exist in a well-developed condition, but they are

14 THE HISTORY OF CEEATION.

covered by membrane, so that no ray of light can enter,
and they can never see. Such eyes, without the function
of sight, are found in several species of moles and mice which
live underground, in serpents and lizards, in amphibious
animals (Proteus, Csecilia), and in fishes ; also in numerous
invertebrate animals, which pass their lives in the dark,
as do many beetles, crabs, snails, worms, etc.

An abundance of the most interesting examples of rudi-
mentary organs is furnished by Comparative Osteology, or
the study of the skeletons of vertebrate animals, one of the
most attractive branches of Comparative Anatomy. In most
of the vertebrate animals we find two pairs of limbs on the
body, a pair of fore-legs and a pair of hind-legs. Very often,
however, one or the other pair is imperfect; it is seldom
that both are, as in the case of serpents and some varieties of
eel-like fish. But some serpents, viz. the giant serpents (Boa,
Python), have stiR in the hinder portion of the body some
useless little bones, which are the remains of lost hind-legs.

In like manner the mammals of the whale tribe (Cetacea),
which have only fore-legs fully developed (breast-fins j, have
further back in their body another pair of utterly superfluous
bones, which are remnants of undeveloped hind-legs. The
same thing occurs in many genuine fishes, in which the
hind-leo^s have in like manner been lost.

Again, in our slow- worm (Anguis), and in some other
lizards, no fore-legs exist, although they have a perfect
shoulder apparatus within their bodies, which should serve
as a means of afiixing the legs. Moreover, in various ver-
tebrate animals, the single bones of both pairs of legs are
found in all the difierent stages of imperfection, and often
the decfenerate bones and those muscles belonging to them

RUDIMENTARY ORGANS. 1 5

are partially preserved, without their being able in any way
to perform any function. The instrument is still there, but
it can no longer play.

Moreover, we can, almost as generally, find rudimentary
organs in the blossoms of plants, inasmuch as one part or
another of the male organs of propagation — the stamen and
anther, or of the female organs of propagation — the style,
germ, etc. — is more or Jess imperfect or abortive. Among
these we can trace, in various closely connected species of
plants, the organ in all stages of degeneration. Thus, for
example, the great natural family of lip-blossomed plants
(Labiat?e), to which the balm, peppermint, marjoram, ground-
ivy, thyme, etc., belong, are distinguished by the fact that
their mouth-like, two-lipped flower contains two long and
two short stamens. But in many exceptional plants of this
family, e, g. in different species of sage, and in the rosemary,
only one pair of stamens is developed; the other pair is more
or less imperfect, or has quite disappeared. Sometimes
stamens exist, but without the anthers, so that they are
utterly useless. Less frequently the rudiment or imperfect
remnant of a fifth stamen is found, physiologically (for the
functions of life) quite useless, but morphologically (for the
knowledge of the form and of the natural relationship)
a most valuable organ. In my "General Morphology
of Organisms," * in the chapter on " Purposelessness, or
Dysteleology," I have given a great number of other
examples (Gen, Morph. ii. 226).

No biological phenomenon has perhaps ever placed
zoologists or botanists in greater embarrassment than these
rudimentary or abortive organs. They are instruments
without employment, parts of the body which exist without

1 6 THE HISTOEY OF CREATION.

performing any service — adapted for a purpose, but without
in reality fulfilling that purpose. When we consider the
attempts which the earlier naturalists have made in order
to explain this mystery, we can scarcely help smiling at the
strange ideas to which they were led. Being unable to find
a true explanation, they came, for example, to the conclu-
sion that the Creator had placed these organs there "for the
sake of symmetry," or they believed that it had appeared
unwise and unsuitable to the Creator (seeing that their
nearest kin did possess such organs) that these organs
should be completely wanting in creatures, where they
are incapable of performing a function, and where it
cannot be otherwise from the special mode of life. In
compensation for the non-existing function, he had at least
furnished them with the outward but empty form ; nearly
in the same manner as civil ofiicers, in uniform, are furnished
with an innocent sword, which is never dra^yn from the
scabbard. I scarcely believe, however, that any of my
readers will be content with such an explanation.

Now, it is precisely this widely spread and mysterious
phenomenon of rudimentary organs, in regard to which all
other attempts at explanation fail, which is perfectly ex-
plained, and indeed in the simplest and clearest way, by
Darwin's Theory of Inheritance and Adaptation. We can
trace the important laws of inheritance and adaptation in
the domestic animals which we breed, and the plants which
we cultivate ; and a series of such laws of inheritance have
already been established. Without going further into this
at present, I will only remark that some of them perfectly
explain, in a mechanical way, the coming into existence of
rudimentary organs, so that we must look u})on the appear-

RUDIMENTARY ORGANS. I 7

ance of such structures as an entirely natural process, arising
from the disuse of the organs.

By adaptation to special conditions of life, the formerly
active and really working organs have gradually ceased
to be used or employed. In consequence of their not being
exercised they have become more and more imperfect, but
in spite of this have always been handed down from one
generation to another by inheritance, until at last they
vanish partially or entirely. Now, if we admit that all
the vertebrate animals mentioned above are derived from
one common ancestor, possessing two seeing eyes and two
well developed pairs of legs, the different stages of suppres-
sion and degeneration of these organs are easily accounted
for in such of the descendants as could no longer use them.
In like manner the various stages of suppression of the
stamens, originally existing to the number of five (in the
flower-bud), among the Labiatge is explained, if we admit
tliat all the plants of this family sprung from one common
ancestor, provided with ^ve stamens.

I have here spoken somewhat fully of the phenomena of
rudimentary organs, because they are of the utmost general
importance, and because they lead us to the great, general,
and fundamental questions in philosophy and natural
science, for the solution of which the Theory of Descent
has now become the indispensable guide. As soon, in fact,
as, according to this theory, we acknowledge the exclusive
activity of physico-chemical causes in living (organic)
bodies, as well as in so-called inanimate (inorganic) nature,
we concede exclusive dominion to that view of the uni-
verse, which we may designate as the mechanical, and
which is opposed to the teleological conception. If we

1 8 THE HISTORY OF CREATION.

compare all the ideas of tlie universe prevalent among
different nations at different times, we can divide them
all into two sharply contrasted groups — a causal or rtie-
chanical, and a teleological or vitalistic. The latter has pre-
vailed generally in Biology until now, and accordingly the
animal and vegetable kingdoms have been considered as
the products of a creative power, acting for a definite pur-
pose. In the contemplation of every organism the unavoid-
able conviction seemed to press itself upon us, that such a
wonderful machine, so complicated an apparatus for motion
as exists in the organism, could only be produced by a
power analogous to, but infinitely more perfect than, the
power of man in the construction of his machines.

However sublime the former idea of a Creator, and his
creative power, may have been ; however much it may be
attempted to divest it of all human analogy, yet in the end
this analogy still remains unavoidable and necessary in the
teleological conception of natui^e. In reality the Creator
must himself be conceived of as an organism, that is, as a
being who, analogous to man, even though in an infinitely
more perfect form, reflects on his constructive power, lays
down a plan of his mechanisms, and then, by the application
of suitable materials, makes them answer their purpose.
Such conceptions necessarily suffer from the fundamental
error of anthropomorphism, or man-likening. In such a
view, however exalted the Creator may be imagined, we
assigTi to him the human attributes of designing a plan,
and therefrom suitably constructing the organism. This is,
in fact, quite clearly expressed in that view which is most
sharply opposed to Darwin's theory, and which has found
among naturalists its most disting-uished representative in

THE TELEOLOGICAL VIEW. 1 9

Agassiz. His celebrated work, " An Essay on Classifica-
tion," ^ which is entirely opposed to Darwin's, and appeared
almost at the same time, has elaborated quite consistently,
and to the utmost extent, these anthropomorphic conceptions
of the Creator.

I maintain with regard to the much-talked-of "purpose
in nature," that it really has no existence but for those
persons who observe phenomena in animals and plants in
the most superficial manner. Without going more deeply
into the matter, we can see at once that the rudimentary
organs are a formidable obstacle to this theory. And, indeed,
every one who makes a really close study of the organization
and mode of life of the various animals and plants, and
becomes familiar with the reciprocity or inter-action of the
phenomena of life, and the so-called " economy of nature,"
must necessarily come to the conclusion that this
*' purposiveness " no more exists than the much-talked-of
" beneficence " of the Creator. These optimistic views have,
unfortunately, as little real foundation as the favourite
phrase, the " moral order of the universe," which is illustrated
in an ironical way by the history of all nations. The
dominion of the " moral " popes, and their pious inquisition,
in the mediaeval times, is not less significant of this than
the present prevailing militarism, with its " moral "
apparatus of needle-guns and other refined instruments of
murder.

If we contemplate the common life and the mutual rela-
tions between plants and animals (man included), we shall
find everywhere, and at all times, the very opposite of that
kindly and peaceful social life which the goodness of the
Creator ought to have prepared for his creatures — we shall

20 THE HISTORY OF CREATION.

ratliGr find everywliere a pitiless, most embittered Struggle
of All against All. Nowhere in nature, no matter where
we turn our eyes, does that idyllic peace, celebrated by
the poets, exist ; we find everywhere a struggle and a
striving to annihilate neighbours and competitors. Passion
and selfishness — conscious or unconscious — is everywhere
the motive force of life. The well-known words of the
German poet —

** Die Welt ist vollkommen iiberall
Wo der Menscli nicht hinkommt mit seiner Qual." *

are beautiful, but, unfortunately, not true. Man in this re-
spect certainly forms no exception to the rest of the animal
world. The remarks which we shall have to make on the
theory of " Struggle for Existence " will sufficiently justify
this assertion. It is, in fact, Darwin who has placed this
important point, in its high and general significance, very
clearly before our eyes, and the chapter in his theory
which he himself calls " Struggle for Existence " is one of
the most important parts of it.

Wliilst, then, we emphatically oppose the vital or
teleological view of animate nature which presents animal
and vegetable forms as the productions of a kind Creator,
acting for a definite purpose, or of a creative, natural
force acting for a definite purpose, we must, on the other
hand, decidedly adopt that view of the universe which is
called the ^mechanical or causal. It may also be called the
monistic, or single-principle theory, as opposed to the tivo-
folcl principle, or dualistic theory, which is necessarily
implied in the teleological conception of the universe. The

* The world is perfect save where Man
Comes in with his stiife.

PHYSICS AND BIOLOGY. 21

mechanical view of nature has for many years been so
firmly established in certain domains of natural science, that
it is here unnecessary to say much about it. It no longer
occurs to physicists, chemists, mineralogists, or astronomers,
to seek to find in the phenomena which continually appear
before them in their scientific domain the action of a Creator
acting for a definite purpose. They universally, and with-
out hesitation, look upon the phenomena which appear in
their different departments of study as the necessary and
invariable effects of physical and chemical forces which are
inherent in matter. Thus far their view is purely material-
istic, in a certain sense of that " word of many meanings."

When a physicist traces the phenomena of motion in elec-
tricity or magnetism, the fall of a heavy body, or the
undulations in the waves of light, he never, in the whole
course of his research, thinks of looking for the interference
of a supernatural power. In this respect. Biology, as the
science of so-called " animated " natural bodies, was formerly
placed in sharp opposition to the above-mentioned inorganic
natural sciences (Anorganology). It is true modern Physi-
ology, the science of the phenomena of motion in animals
and plants, has completely adopted the mechanical view ; but
Morphology, the science of the forms of animals and plants,
has not been affected at all by it. Morphologists, in spite of
the position of physiology, have continued, as before, in oppo-
sition to the mechanical view of functions, to look upon the
forms of animals and plants as something which cannot be
at all explained mechanically, but which must owe its origin
necessarily to a higher, supernatural creative power, acting
for a definite purpose.

In this general view it is quite indifferent whether the

22 THE HISTOEY OF CREATION.

creative power be worshipped as a personal god, or whether
it be termed the power of life (vis vitalis), or final cause
(causa finalis). In any case, to express it in one word, its
supporters have recourse to a miracle for an explanation.
They throw themselves into the arms of a poetic faith,
which as such can have no value in the domain of scientific
knowledge.

All that was done before Darwin, to establish a natural
mechanical conception of the origin of animals and plants,
has been in vain, and until his time no theory gained a
general recognition. Darwin's theory first succeeded in
doino: this, and thus has rendered an immense service. For
the idea of the unity of organic and inorganic nature
is now firmly established; and that branch of natural
science which had longest and most obstinately opposed
mechanical conception and explanation, viz. the science of
the structure of animate forms, is launched on to identically
the same road towards perfection as that along which all the
rest of the natural sciences are travelling. The unity of all
natural phenomena is by Darwin's theory finally established.

This unity of all nature, the animating of all matter, the
inseparability of mental power and corporeal substance,
Goethe has asserted in the words : " Matter can never exist
and be active without mind, nor can mind without matter."
These first principles of the mechanical conception of the
universe have been taught by the great monistic philosophers
of all ages. Even Democritus of Abdera, the immortal
founder of the Atomic theory, clearly expressed them about
500 years before Christ; but the great Dominican friar,
Giordano Bruno, did so even more explicitly. For this he
was burnt at the stake, by the Christian inquisition in

ALL NATUEE IS ANIMATE. 23

Rome, on the ITtli of Feb., 1600, on the same day on
which, 36 years before, Galileo, his great fellow-countryman
and fellow-worker, was born. Such men, who live and die
for a great idea, are usually stigmatized as " materialists " ;
but their opponents, whose arguments were torture and the
stake, are praised as " spiritualists."

By the Theory of Descent we are for the first time enabled
to conceive of the unity of nature in such a manner that
a mechanico-causal explanation of even the most intricate
organic phenomena, for example, the origin and structure
of the organs of sense, is no more difficult (in a general
way) than is the mechanical explanation of any physical
process ; as, for example, earthquakes, the courses of the wind,
or the currents of the ocean. We thus arrive at the
extremely important conviction that all natural bodies
which are known to us are equally anmiated, that the
distinction which has been made between animate and
inanimate bodies does not exist. When a stone is thrown
into the air, and falls to earth according to definite laws, or
when in a solution of salt a crystal is formed, the phenomenon
is neither more nor less a mechanical manifestation of life
than the growth and flowering of plants, than the propaga-
tion of animals or the activity of their senses, than the
perception or the formation of thought in man. This
final triumph of the monistic conception of nature consti-
tutes the highest and most general merit of the Theory of
Descent, as reformed by Darwin.

24 THE HISTORY OF CREATION.

CHAPTER II.

SCIENTIFIC JUSTIFICATION OF THE THEORY OF DE-
SCENT. HISTORY OF CREATION ACCORDING TO

LINN^US.

The Theory of Descent, or Doctrine of Filiation, as the Monistic Explana-
tion of Organic Natural Phenomena. — Its Comparisoa with Newton's
Theory of Gravitation. — Limits of Scientific Explanation and of Human
Knowledge in general. — All Knowledge founded originally on Sensuous
Experience, d posteriori. — Transition of d posteriori knowledge, by In-
heritance, into d priori knowledge. — Contrast between the Supernatural
Hypotheses of the Creation according to Linnseus, Cuvier, Agassiz, and
the Natural Theories of Development according to Lamarck, Goethe,
and Darwin. — Connection of the former with the Monistic (mechanical),
of the latter with the Dualistic Conception of the Universe. — Monism
and Materialism. — Scientific and Moral Materialism. — The History of
Creation according to Moses. — Linnaeus as the Founder of the Systematic
Description of Natui'e and Distinction of Species. — Linnaeus' Classifica-
tion and Binary Nomenclature. — Meaning of Linnaeus' Idea of Species.
— His History of Creation. — Linnasus' view of the Origin of Species.

The value which every scientific theory possesses is
measured by the number and importance of the objects
which can be explained by it, as well as by the simplicity
and universality of the causes which are employed in it as
grounds of explanation. On the one hand, the greater the
number and the more important the meaning of the
phenomena explained by the theory, and the simpler, on
the other hand, and the more general the causes which the
theory assigns as explanations, the greater is its scientific

NEWTON AND DAKWIN. 25

value, the more safely we are guided by it, and the more
strongly are we bound to adopt it.

Let us call to mind, for example, that theory which has
ranked up to the present time as the greatest achievement
of the human mind — the Theory of Gravitation, which
Newton, two hundred years ago, established in his Mathe-
matical Principles of Natural Philosophy. Here we find
that the object to be explained is as large as one can well
imagine. He undertook to reduce the phenomena of the
motion of the planets, and the structure of the universe, to
mathematical laws. As the most simple cause of these in-
tricate phenomena of motion, Newton established the law
of weight or attraction, the same law which is the cause of
the fall of bodies, of adhesion, cohesion, and many other
phenomena.

If we apply the same standard of valuation to Darwin's
theory, we must arrive at the conclusion that this theory,
also, is one of the greatest achievements of the human mind,
and that it may be placed quite on a level with Newton's
Theory of Gravitation. Perhaps this opinion will seem a
little exaggerated, or at any rate very bold, but I hope in
the course of this treatise to convince the reader that this
estimate is not too high. In the preceding chapter, some
of the most important and most general phenomena in
organic nature, which have been explained by Darwin's
theory, have been named. Among them are the varia-
tions in form which accompany the individual development
of organisms, most varied and complicated phenomena,
which until now presented the greatest difficulties in the
way of mechanical explanation, that is, in the tracing of
them to active causes. We have mentioned the rudmnen-

26 THE HISTORY OF CREATION.

tary organs, those exceedingly remarkable structures in
animals and plants which have no object and refute every
teleological explanation seeking for the final purpose of the
organism. A great number of other phenomena might have
been mentioned, which are no less important, and are ex-
plained in the simplest manner by Darwin's reformed
Theory of Descent. For the present I will only mention
the phenom^ena presented to us by the geographical distri-
hution of animals and plants on the surface of our planet,
as well as the geological distribution of the extinct and
petrified organisms in the different strata of the earth's
crust. These important palseontological and geographical
phenomena, which were formerly only known to us as facts,
are now traced to their active causes by the Theory of
Descent.

The same statement applies fui'ther to all the general laws
of Comparative Anatomy, especially to the great law of
division of labour or seioaration (polymorphism, or dif-
ferentiation), a law which determines the form or structure
of human society, as well as the organization of individual
animals and plants. It is this law which necessitates an
ever increasing variety, as well as a progressive develop-
ment of organic forms. This law of the division of labour
has, up to the present time, been only recognized as a fact,
and it, like the law of progressive development, or the law
of progress which we perceive active everywhere in the
history of nations (as also in that of animals and plants), is
explained by Darwin's Doctrine of Descent. Then, if we
turn our attention to the great whole of organic nature, if
we compare all the individual groups of phenomena of this
immense domain of life, it cannot fail to appear, in the light

NATURE OF DARWIN's THEORY. 27

of the Doctrine of Descent, no longer as the ingeniously
desig-ned work of a Creator building up according to a
definite purpose, but as the necessary consequence of active
causes, which are inherent in the chemical combination of
matter itself, and in its physical properties.

In fact, we can most positively assert, and I shall justify
this assertion in the course of these pages, that by the Doc-
trine of Filiation, or Descent, we are enabled for the first time
to reduce all organic phenomena to a single law, and to dis-
cover a single active cause for the infinitely intricate
mechanism of the whole of this rich world of phenomena.
In this respect, Darwin's theory stands quite on a level with
Newton's Theory of Gravitation ; indeed, it even rises higher
than Newton's theory !

The grounds of explanation are equally simple in the two
theories. In explaining this most intricate world of phe-
nomena, Darwin does not make use of new or hitherto
unknown properties of matter, nor does he, as one might
suppose, make use of discoveries of new combinations
of matter or of new forces of organization ; but it is
simply by extremely ingenious combination, by the syn-
thetic comprehension, and by the thoughtful compa-
rison of a number of well-knoAvn facts, that Darwin has
solved the "holy mystery " of the living world of forms. The
consideration of the interchanging relations which exist
between two general properties of organisms, viz. Inherit-
ance and Adaptation, is what has here been of the first
importance. Merely by considering the relations between
these two vital actions or physiological functions of organ-
isms, also further by considering the reciprocal inter-action
which all animals and plants, living in one and the same

28 THE HISTORY OF CREATIOX.

place, necessarily exert on one another — solely by the correct
estimate of these simple facts, and by skilfully combining
them, Darwin has succeeded in finding the true active
causes (causag efficientes) of the immensely intricate world
of forms in organic nature.

In any case we are in duty bound to accept this theory
till a better one be found, which will undertake to explain
the same amount of facts in an equally simple manner.
Until now we have been in utter want of such a theory.
The fundamental idea that all different animal and vege-
table forms must be descended from a few or even from one
single, most simple primary form, was indeed not new. This
idea was long since distinctly formulated — first by the great
Lamarck, at the beginning of our century. But Lamarck
in reality only expressed the hypothesis of the Doctrine of
Filiation, without establishing it by an explanation of the
active causes. And it is just the demonstration of these
causes which marks the extraordinary progress which
Darwin's theory has made beyond that of Lamarck. In
the physiological properties of Inheritance and Adaptation
of orofanic matter, Darwin discovered the true cause of the
genealogical relationship of organisms. It was not possible
for the genius of Lamarck in his day to command that
colossal material of biological facts which has been collected
by the patient zoological and botanical investigations of the
last fifty years, and which has been used by Darwin as an
overpowering apparatus of evidence.

Darwin's theory is therefore not what his opponents fre-
quently represent it as being — an unwarranted hypothesis
taken up at random. It is not for zoologists or botanists to
accept or reject this as an explanatory theory, as they

DARWINISM NOT AN HYPOTHESIS. 29

please ; they are rather compelled and obliged to accept
it, according to the general principle observed in all natural
sciences, that we must accept and retain for the explanation
of phenomena any theory which, though it has only a
feeble basis, is compatible with the actual facts — until it is
replaced by a better one. If we do not adopt it, we re-
nounce a scientific explanation of phenomena, and this is,
in fact, the position which many biologists still maintain.
They look upon the whole domain of animate nature as a
perfect mystery, and upon the origin of animals and plants,
the phenomena of their development and affinities, as quite
inexplicable and miraculous; in fact, they will not allow that
there can be a true understanding of them.

Those opponents of Darwin who do not exactly \\dsh to
renounce a scientific explanation are in the habit of saying,
" Darwin's theory of the common origin of the different
species is only one hypothesis; we oppose to it another,
the hypothesis that the individual animal and vegetable
species have not developed one from another by descent,
but that they have come into existence independently of
one another, by a still undiscovered law of nature." But as
long as it is not shown how this coming into existence is
to be conceived of, and what that " law of nature " is — as
long as not even probable grounds of explanation can be
brought forward to account for the independent coming
into existence of animal and vegetable species, so long this
counter-hypothesis is in fact no hypothesis, but an empty
unmeaning phrase. Darwin's theory ought, moreover, not
to be called an hypothesis. For a scientific hypothesis
is a supposition, postulating the existence of unknown

properties or motional phenomena of natural bodies, wliich
3

30 THE HISTOEY OF CREATION.

properties have not as yet been observed by the experience
of the senses. But Da^^win's theory does not assume such
unknown conditions ; it is based upon general properties
of organisms that have long been recognized, and — as has
been remarked — it is the exceedingly ingenious and com-
prehensive combination of a number of phenomena which
had hitherto stood isolated, which gives the theory its
extraordinarily great and intrinsic value. By it we are
for the first time in a position to demonstrate an active
cause for all the known morphological phenomena in the
animal and vegetable kingdoms; and, in fact, this cause is
always one and the same, viz. the alternate action of Adap-
tation and Inheritance, therefore a physiological, that is, a
physico-chemical or mechanical, relationship. For these
reasons the acceptance of the Doctrine of Filiation, as
mechanically established by Darwin, is a binding and un-
avoidable necessity for the whole domain of zoology and
botany.

As, therefore, in my opinion the immense importance of
Darwin's theory lies in the fact that it has mechanically
explained those organic phenomena of for'.ns which had
hitherto been unexplained, it is perhaps necessary that I
should here say a few words about the different ideas con-
nected with the word " explanation." It is very frequently
said, in opposition to Darwin's theory, that it does indeed
explain those phenomena by Inheritance and Adaptation,
but that it does not at the same time explain those pro-
perties of organic matter, and that therefore we do not
arrive at first causes. This objection is quite correct, but it
applies equally to all explanations of phenomena. We no-
where arrive at a knowledge of fii'st causes. The origin of

INNATE KNOWLEDGE. 3 I

every simple salt crystal, which we obtain by evaporating
its mother liquor, is no less mysterious to us, as far as con-
cerns its first cause, and in itself no less incomprehensible
than the origin of every animal which is developed out
of a simple cell. In explaining the most simple physical or
chemical phenomena, as the falling of a stone, or the forma-
tion of a chemical combination, we arrive, by discovering
and establishing the active causes — for example, the gravi-
tation or the chemical affinity — at other remoter phenomena,
which in themselves are mysterious. This arises from the
limitation or relativity of our powers of understanding.
We must not forget that human knowledge is absolutely
limited, and possesses only a relative extension. It is, in
its essence, limited by the very nature of our senses and of
our brains.

All knowledge springs from sensuous perceptions. In
opposition to this statement, the innate, d priori know-
ledge of man may be brought up ; but we can see that the
so-called d priori knowledge can by Darwin's theory be
proved to have been acquired d posteriori, being based on
experience as its first cause. Knowledge which is based
originally upon purely empirical observations, and which is
therefore a purely sensuous experience, but has then been
transmitted from generation to generation by inheritance,
appears in later generations as if it were independent,
innate, and a priori. In our late animal ancestors, all our
so-called " a priori knowledge " was originally acquired d
posteriori, and only gradually became d p)riori by inherit-
ance. It is based in the first instance upon experiences,
and by the laws of Inheritance and Adaptation we can
positively prove that knowledge d priori and knowledge d

32 THE HISTORY OF CREATION.

posteriori cannot rightly be placed in opposition, as is
usually done. On the contrary, sensuous experience is
the original source of all knowledge. For this reason alone,
all oui' knowledge is limited, and we can never apprehend
the first causes of any phenomena. The force of crystal-
lization, the force of gravitation, and chemical affinity
remain in themselves just as incomprehensible as do
Adaptation and Inheritance.

Seeing that Darwin's theory explains from a single point
of view the totality of all those phenomena of which we
have given a brief survey, that it demonstrates one and
the same quality of the organism as the active cause in all
cases, we must allow that it gives us for the present all
that we can desire. Moreover, we have good reason to hope
that at some future time we shall learn to explain the first
causes at which Darwin has arrived, namely, the properties
of Adaptation and Inheritance ; and that we shall succeed in
discovering in the composition of albuminous matter certain
molecular relations as the remoter, simpler causes of these
phenomena. There is indeed no prospect of this in the
immediate future, and we content ourselves for the present
with the tracing back of organic phenomena to two
mysterious properties, just as in the case of Newton's
theory we are satisfied with tracing the planetary motions
to the force of gravitation, which itself is likewise a mys-
tery to us and not cognizable in itself.

Before commencing our principal task, which is the care-
ful discussion of the Doctrine of Descent, and the conse-
quences that arise out of it, let us take an historical retro-
spect of the most important and most widely spread of those
views, which before Darwin men had elaborated concernin^^

I

THE MOSAIC COSMOGENY. 33

organic creation, and the coming into existence of the many
animal and vegetable species. In doing this I have no inten-
tion of entertaining the reader with a statement of all
the innumerable stories about the creation which have
been current among the different human species, races, or
tribes. However interesting and gratifying this task would
be, from an ethnographical point of view, as well as in a
history of civilization, it would lead us here much too far
from our subject. Besides, the great majority of all these
legends about creation bear too clearly the stamp of arbi-
trary fiction, and of a want of a close observance of nature, to
be of interest in a scientific treatment of the history of crea-
tion. I shall therefore only select the Mosaic history from
among those that are not founded on scientific investigation,
on account of the unparalleled influence which it has gained
in the western civilized world ; and then I shall immedi-
ately take up the scientific hypothesis about creation, which
originated with Linnseus as late as the commencement of
last century.

All the different conceptions which man has ever formed
about the coming into existence of the diflferent animal and
vegetable species may conveniently be divided into two
great contrasted groups — the natural and supernatural his-
tories of creation.

These two groups, on the whole, correspond with the two
different principal forms of the human notions of the uni-
verse which we have already contrasted as the ruionistic and
the dualistic conception of nature. In the usual dualistic or
teleological (vital) conception of the universe, organic nature
is regarded as the purposely executed production of a Creator
working according to a definite plan. Its adherents see in

34 THE HISTOEY OF CREATION.

every individual species of animal and plant an " embodied
creative tliouglit," the material expression of a definite first
cause (causa finalis) acting for a set purpose. They must
necsssarily assume supernatural (not mechanical) processes
for the origin of organisms. With justice, we may therefore
designate their scheme of the world's gTowth as the Super-
natural History of Creation. Among all such teleological
histories of creation, that of Moses has gained the gTcatest
influence, since even so -distinguished a naturalist as Lin-
na3us has claimed admittance for it in Natural Science.
Cuvier's and Agassiz's views of creation also belong to this
group, as do in fact those of the great majority of both
scientific and unscientific men.

On the other hand, the theory of development carried out
by Darwin, which we shall have to treat of here as the Non-
Tiiiraculous or Natural History of Creation, and which has
already been put forward by Goethe and Lamarck, must,
if carried out logically, lead to the monistic or mechan-
ical (causal) conception of the universe. In opposition to
the dualistic or teleological conception of natm-e, our theory
considers organic, as well as inorganic, bodies to be the neces-
sary products of natural forces. It does not see in every in-
dividual species of animal and plant the embodied thought
of a personal Creator, but the expression for the time being
of a mechanical process of development of matter, the ex-
pression of a necessarily active cause, that is, of a mechanical
cause (causa efiiciens). Where teleological Dualism seeks
the arbitrary thoughts of a capricious Creator in the miracles
of creation, causal Monism finds in the process of develop-
ment the necessary efiects of eternal immutable laws of
nature.

MATERIALISM. 35

The Monism here maintained by us is often considered
identical with Materialism. Now, as Darwinism, and in
fact the whole theory of development, has been designated as
" materialistic" I cannot avoid here at once guarding myself
against this ambiguous word, and against the malice with
which, in certain quarters, it is employed to stigmatize our
doctrine.

By the word "Materialism',' two completely different
things are very frequently confounded and mixed up, which
in reality have nothing Avhatever to do with each other,
namely, scientific and moral materialism. Scientific mate-
rialism, which is identical with our Monism, afiirms in
reality no more than that everything in the world goes on
naturally — that every effect has its cause, and every cause its
effect. It therefore assigns to causal law — that is, the law
of a necessary connection between cause and effect — its
place over the entire series of phenomena that can be
known. At the same time, scientific materialism positively
rejects every belief in the miraculous, and every conception,
in whatever form it appears, of supernatural processes.
Accordingly, nowhere in the whole domain of human know-
ledge does it recognize real metaphysics, but throughout
only physics ; through it the inseparable connection between
matter, form, and force becomes self evident. This scientific
materialism has long since been so universally acknowledged
in the wide domain of inorganic science, in Physics and
Chemistry, in Mineralogy and Geology, that no one now
doubts its sole authority. But in Biology, or Organic science,
the case is very different; here its value is still continually a
matter of dispute in many quarters. There is, however,
nothing else which can be set up against it, excepting the

3^ THE HISTORY OF CREATION.

metaphysical spectre of a vital power, or empty theological
dogma. If we can prove that all nature, so far as it can be
known, is only one, that the same "great, eternal, iron
laws" are active in the life of animals and plants, as in
the growth of crystals and in the force of steam, we may
with reason i^naintain the monistic or mechanical view
of things throughout the domain of Biology — in Zoology and
Botany — whether it be stigmatized as "materialism " or not.
In such a sense all exact science, and the law of cause and
effect at its head, is purely materialistic.

Moral, or ethical Materialism, is something quite distinct
from scientific materialism, and has nothing whatever in
common with the latter. This real materialism proposes
no other aim to man in the course of his life than
the most refined possible gratification of his senses. It is
based on the delusion that purely material enjoyment
can alone give satisfaction to man ; but as he can find that
satisfaction in no one form of sensuous pleasure, he dashes on
weariedly from one to another. The profound truth that the
real value of life does not lie in material enjoyment, but in
moral action — that true happiness does not depend upon
external possessions, but only in a virtuous course of Life —
this is unknown to ethical materialism. We therefore look
in vain for such materialism among naturalists and phi-
losophers, whose highest happiness is the intellectual
enjoyment of Nature, and whose highest aim is the know-
ledge of her laws. We find it in the palaces of ecclesi-
astical princes, and in those hypocrites who, under the
outward mask of a pious worship of God, solely aim at
hierarchical tyranny over, and material spoliation of, their
felloAv-men. Blind to the infinite grandeur of the so-called

MOKAL MATERIALISM. 37

"raw material," and the glorious world of phenomena
arising* from it — insensible to the inexhaustible charms
of Nature, and without a knowledge of her laws — they
stigmatize all natural science, and the culture arising from
it, as sinful " materialism," while really it is this which they
themselves exhibit in a most shocking form. Satisfactory
proofs of this are furnished, not only by the whole history
of the Catholic Popes, with their long series of crimes, but
also by the history of the morals of orthodoxy in every
form of religion.

In order, then, to avoid in future the usual confusion of
this utterly objectionable Moral Materialism with our
Scientific Materialism, we think it necessary to call the
latter either Monism or Realism. The principle of this
Monism is the same as what Kant terms the " principle of
mechanism," and of which he expressly asserts, thsit without
it there can he no natural science at all. This principle is
quite inseparable from our Non-miraculous History of Crea-
tion, and characterizes it as opposed to the teleological belief
in the miracles of a Supernatural History of Creation.

Let us now first of all glance at the most important of all
the supernatural histories of creation, I mean that of
Moses, as it has been handed down to us in the Bible, the
ancient document of the history and laws of the Jewish
people. The Mosaic history of creation, since in the first
chapter of Genesis it forms the introduction to the Old
Testament, has enjoyed, down to the present day, general
recognition in the whole Jewish and Christian world of
civilization. Its extraordinary success is explained not
only by its close connection with Jewish and Christian
doctrines, but also by the simple and natural chain of ideas

38 THE HISTORY OF CREATION.

which runs through it, and which contrasts favourably
with the confused mythology of creation current among
most of the other ancient nations. First the Lord God
creates the earth as an inorganic body ; then he separates
light from darkness, then water from the dry land. Now
the earth has become inhabitable for organisms, and plants
are first created, animals later — and among the latter the
inhabitants of the water and the air first, afterwards the
inhabitants of the dry land. Finally God creates man, the
last of all organisms, in his own image, and as the ruler of
the earth.

Two gTeat and fundamental ideas, common also to the
non-miraculous theory of development, meet us in this
Mosaic hypothesis of creation, with surprising clearness and
simplicity — the idea of separation or differentiation, and the
idea of progressive development or ])erfecting. Although
Moses looks upon the results of the great laws of organic
development (which we shall later point out as the necessary
conclusions of the Doctrine of Descent) as the direct actions
of a constructing Creator, yet in his theory there lies hidden
the ruling idea of a progressive development and a difieren-
tiation of the originally simple matter. We can therefore
bestow our just and sincere admiration on the Jewish
lawgiver's gTand insight into natui^e, and his simple and
natural hypothesis of creation, without discovering in it a
so-called " divine revelation," That it cannot be such is clear
from the fact that two great fundamental errors are asserted
in it, namely, first, the geocentric error that the earth is the
fixed central point of the whole universe, round which the
sun, moon, and stars move; and secondly, the anthropocentric
error, that man is the premeditated aim of the creation of

THE BIBLE AND SCIENCE. 39

the earth, for whose service alone all the rest of nature is
said to have been created. The former of these errors was
demolished by Copernicus' System of the Universe in the
beginning of the 16th century, the latter by Lamarck's
Doctrine of Descent in the beginning of the 19th century.

Although the geocentric error of the Mosaic history was
demonstrated by Copernicus, and thereby its authority as
an absolutely perfect divine revelation was destroyed, yet it
has maintained, down to the present day, such influence,
that it forms in many wide circles the principle obstacle to
the adoption of a natural theory of development. Even
in our century, many naturalists, especially geologists,
have tried to bring the Mosaic theory into harmony
with the recent results of natural science, and have, for
example, interpreted Moses' seven days of creation as seven
great geological periods. However, all these ingenious
attempts at interpretation have so utterly failed, that they
require no refutation here. The Bible is no scientific book,
but consists of records of the history, the laws, and the
religion of the Jewish people, the high merit of which, as a
history of civilization, is not impaired by the fact that in all
scientific questions it has no commanding importance, and is
full of gross errors.

"We may now make a great stride over more than three
thousand years, from Moses, who died about the year 1480
before Christ, to Linnaeus, who was born in the year 1707
after Christ. During this whole period no history of creation
was brought forward that gained any lasting importance, or
the closer examination of which would here be of any
interest. Indeed, during the last fifteen hundred years,
since Christianity gained its supremacy, the Mosaic history

40 THE HISTORY OF CREATION.

of creation, together with the dogmas connected with it, has
become so generally predominant, that the 19th century is
the first that has dared positively to rise against it. Even
the great Swedish naturalist, Linnaeus, the founder of modern
natural history, linked his System of Nature most closely to
the Mosaic history of creation.

The extraordinary progress which Charles Linnaeus made
in the so-called descriptive natural sciences, consists, as is
well known, in his having established a system of nomencla-
ture of animals and plants, which he carried out in a manner
so perfectly logical and consistent, that down to the present
day it has remained in many respects the standard for all
succeeding naturalists engaged in the study of the forms of
animals and plants. Although Linnaeus' system was
artificial, although in classifying animal and vegetable
species he only sought and employed single parts as the
foundation for his divisions, it has, nevertheless, gained the
greatest success ; firstly, in consequence of its being carried
out consistently, and secondly, by its nomenclature of natural
bodies, which has become extremely important, and at
which we must here briefly glance.

Before Linnaeus' time, many vain attempts had been made
to throw light upon the endless chaos of difi'erent animal
and vegetable forms (then known) by adopting for them
suitable names and groupings ; but Linnaeus, by a happy hit,
succeeded in accomplishing this important and difllcult task,
when he established the so-called " binary nomenclature."
The binary nomenclature, or the twofold designation, as
Linnaeus first established it, is still universally applied by
all zoologists and botanists, and will, no doubt, maintain
itself, for a long time to come, with undiminished authority.

LINN^US' NOMENCLATURE. 4I

It consists in this, that every species of animal and plant is
designated by two names, which stand to each other in the
same relation as do the christian and surnames of a man.
The special name which corresponds with the christian
name, and expresses the idea of " a species," serves as the
common designation of all individual animals or plants,
which are equal in all essential matters of form, and are
only distinguished by quite subordinate features. The more
general name, on the other hand, corresponding with the
surname, and which expresses the idea of a genus, serves for
the common designation of all the most nearly similar kinds
or species.

According to Linnaeus' plan, the more general and compre-
hensive generic name is written first ; the special subor-
dinate name of the species follows it. Thus, for example,
the common cat is called Felis domestica; the wild cat,
Felis catus ; the panther, Felis pardus ; the jaguar, Felis onca ;
the tiger, Felis tigris ; the lion, Felis leo. All these six kinds
of animals of prey are different species of one and the
same genus — Felis. Or, to add an example from the vege-
table kingdom, according to Linnseus' designation the pine
is Pinus abies ; the fir, Pinus picea ; the larch, Pinus larix ;
the Italian pine, Pinus pinea ; the Siberian stone pine, Pinus
cembra ; the knee timber, Pinus mughus ; the common pine,
Pinus silvestris. All these seven kinds of pines are different
species of one and the same genus — Pinus.

Perhaps this advance made by Linnaeus may seem to some
only of subordinate importance in the practical distinction
and designation of the variously formed organisms. But in
reality it was of the very greatest importance, both from a
practical and theoretical point of view. For now, for the

42 THE HISTORY OF CREATION.

first time, it became possible to arrange the immense mass of
different organic forms according to tlieir greater or less
degree of resemblance, and to obtain an easy survey of the
general outlines of sucb a "system." Linnseus facilitated
tbe tabulation and survey of this " system " of plants and
animals still more by placing together the most nearly
similar genera into so-called orders (ordines) ; and by
uniting the most nearly similar orders into still more com-
prehensive main divisions or classes. Thus, according to
Linnaeus, each of the two organic kingdoms were broken up
into a number of classes, the vegetable kingdom into twenty-
four, and the animal kingdom into six. Each class again
contains several orders. Every single order may contain
a number of genera, and, again, every single genus several
species.

Valuable as was Linnaeus' binary nomenclature in a prac-
tical way, in bringing about a comprehensive systematic
distinction, designation, arrangement, and division of the
organic world of forms, yet the incalculable theoretical
influence which it gained forthwith in relation to the
history of creation was no less important. Even now all
the important fundamental questions as to the history of
creation turn finally upon the decision of the very
remote and unimportant question, What really are kinds or
species ? Even now the idea of organic species may be
termed the central point of the whole question of creation,
the disputed centre, about the difierent conceptions of
which Darwinists and Anti-Darwinists fight.

According to Darwin's opinion, and that of his adherents,
the difierent species of one and the same genus of animals
and plants are nothing else than difierently developed

WHAT IS A SPECIES 5 43

descendants of one and the same original primary form.
The different kinds of pine mentioned above would accord-
ingly have originated from a single primaeval form of pine.
In like manner the origin of aU the species of cat
mentioned above would be traced to a single common form
of Felis, the ancestor of the whole genus. But further,
in accordance with the Doctrine of Descent, all the
different genera of one and the same order ought also to
be descended from one common primary ancestor, and so, in
like manner, all ordres of a class from a single primary form.

On the other hand, according to the idea of Darwin's
opponents, all species of animals and plants are quite in-
dependent of each other, and only the individuals of each
species have originated from a single primary form. But if
we ask them how they conceive these original primary forms
of each species to have come into existence, they answer
with a leap into the incomprehensible, " They were created."

Linnaeus himself defined the idea of species in this
manner by saying, " There are as many different species as
there were different forms created in the beginning by the
infinite Being." ( " Species tot sunt diversse, quot diversas
formas ab initio creavit infinitum ens.") In this respect,
therefore, he follows most closely the Mosaic history of
creation, which in the same way maintains that animals
and plants were created "each one after its kind." Linnseus,
accepting this, held that originally of each species of
animals and plants either a single individual or a pair had
been created ; in fact a pair, or, as Moses says, "a male
and a female " of those species which have separate sexes,
but of those species in which each individual combines both
sexual organs (hermaphrodites), as for instance the earth-

44 THE HISTORY OF CREATION.

worm, the garden and vineyard snails, as well as the great
majority of plants, a single individual.

Linn&eus further follows the Mosaic legend in regard to the
flood, by supposing that the great general flood destroyed all
existing organisms, except those few individuals of each
species (seven pairs of the birds and of clean animals, one
pair of unclean animals) which Noah saved in the ark, and
which were placed again on land, on Mount Ararat, after the
flood had subsided. He tried to explain the geographical
difficulty of the living together of the most different animals
and plants, as follows : Mount Ararat, in Armenia, being
situated in a warm climate, and rising over 16,000 feet in
height, combines in itself the conditions for a temporary
common abode of such animals as live in different zones.
Accordingly, animals accustomed to the polar regions could
climb up the cold mountain ridges, those accustomed to
a warm climate could go down to the foot of the mountain,
and the inhabitants of a temperate zone could remain mid-
way up the mountain. From this point it was possible for
them to spread north and south over the earth.

It is scarcely necessary to remark that this Linneean
hypothesis of creation, which evidently was intended to
harmonize most closely with the prevailing belief in the
Bible, requires no serious refutation. When we consider
Linnseus' clearness and sagacity in other matters, we may
doubt whether he believed it himself As to the simulta-
neous origin of all individuals of each species from one pair
of ancestors respectively (or in the case of the hermaphro-
dite species, from one original hermaphrodite), it is clearly
quite untenable ; for, apart from other reasons, in the first
days after the creation, the few animals of prey would have

LINN^US HISTORY OF CREATION. 45

sufficed to have utterly demolished all the herbivorous animals,
as the herbivorous animals must have destroyed the few
individuals of the different species of plants. The existence
of such an equilibrium in the economy of nature as obtains
at present cannot possibly be conceived, if only one individual
of each species, or only one pair, had originally and simul-
taneously been created.

Moreover, how little importance Linnseus himself attached
to this untenable hypothesis of creation is clear, among
other things, from the fact that he recognized Hyhridism
(crossing) as a source of the production of new species.
He assumed that a great number of independent new
species had originated by the interbreeding of two different
species. Indeed, such hybrids are not at all rare in nature,
and it is now proved that a great number of species, for
example, of the genus Rubus (bramble), mullen (Verbascum),
willow (Salix), thistle (Cirsium), are hybrids of different
species of these genera. We also know of hybrids between
hares and rabbits (two species of the genus Lepus), further
of hybrids between different species of dog (genus Canis),
etc., which can be propagated as independent species.

It is certainly very remarkable that Linnseus asserted
the physiological (therefore mechanical) origin of new species
in this process of hybridism. It clearly stands in direct
opposition to the supernatural origin of the other species by
creation, which he accepted as put forward in the Mosaic
account. The one set of species would therefore have
originated by dualistic (teleological) creation, the other by
monistic (mechanical) development.

The great and well merited authority which Linnseus
gained by his systematic classification and by his other

46 THE HISTORY OF CREATION.

services to Biology, was clearly the reason why his views of
creation also remained, throughout the whole of the last
century, undisputed and generally recognized. If through-
out systematic Zoology and Botany the distinctions,
classification, and designations of species, introduced by
Linnaeus, and the dogmatic ideas connected therewith had
not been maintained — ^more or less unaltered — we should be
at a loss to understand how his idea of an independent
creation of single species could have stood, by itself, down
to the present day. It is only owing to his great
authority, and through his attaching himself to the prevail-
ing Biblical belief, that his hypothesis of creation has
retained its position so long.

CHAPTER III.

THE HISTORY OF CREATION ACCORDING TO CUYIER

AND AGASSIZ.

General Theoretical Meaning of the Idea of Species. — Distinction between
the Theoretical and Practical Definition of the Idea of Species. — Cuvier's
Definition of Species. — Merits of Cuvier as the Founder of Comparative
Anatomy. — Distinction of the Fonr Principal Forms (types or branches)
of the Animal Kingdom, by Cuvier and Bar. — Cuvier's Services to
Palaeontology. — His Hypothesis of the Revolutions of our Globe, and the
Epochs of Creation separated by them. — Unknown Supernatural Causes
of the Kevolutions, and the subsequent New Creations. — Agassiz's
Teleological System of Nature. — His Conception of the Plan of Creation,
and its six Categories (groups in classification). — Agassiz's Views of the
Creation of Species. — Eude Conception of the Creator as a man-like
being in Agassiz's Hypothesis of Creation. — Its internal Inconsistency
and Contradictions with the important Palaeontological Laws discovered
by Agassiz.

The real matter of dissension in the contest carried on
by naturalists as to the origin of organisms, their creation
and development, lies in the conceptions which are enter-
tained about the nature of species. Naturalists either
agree with Linnaeus, and look upon the different species
as distinct forms of creation, independent of one another,
or they assume with Darwin their blood-relationship.
If we share Linnaeus' view (which was discussed in our
last chapter), that the different organic species came into
existence independently — that they have no blood-relation-

48 THE HISTORY OF CEEATION.

ship — we are forced to admit that they were created
independently, and we must either suppose that every
single organic individual was a special act of creation
(to which surely no naturalist will agree), or we must
derive all individuals of every species from a single in-
dividual, or from a single pair, which did not arise in a
natural manner, but was called into being by command of
a Creator. In so doing, however, we tm^n aside from the
safe domain of a rational knowledge of nature, and take
refuge in the mythological behef in miracles.

If, on the other hand, with Darwin, we refer the simi-
larity of form of the different species to real blood-relation-
ship, we must consider all the different species of animals
and plants as the altered descendants of one or a few most
simple original forms. Viewed in this way, the Natural
System of organisms (that is, their tree-like and branching
arrangement and division into classes, orders, families,
genera, and species) acquires the significance of a real genea-
logical tree, whose root is formed by those original archaic
forms which have long since disappeared. But a truly
natural and consistent view of organisms can assume no
supernatural act of creation for even those simplest original
forms, but only a coming into existence by 'spontaneous
generation* (archigony, or generatio spontanea). From
Darwin's view of the nature of species, we arrive there-
fore at a natural theory of development; but from Lin-
nseus' conception of the idea of species, we must assume a
supernatural dogma of creation.

Most naturalists after Linnseus, whose great services in

♦Archebiosis (Bastian), Abiogenesis (Huxley).

THE DOGMA OF SPECIES. 49

systematic and descriptive natural history won for him
such high authority, followed in his footsteps, and without
further inquiry into the origin of organization, they assumed,
in the sense of Linnaeus, an independent creation of individual
species, in conformity with the Mosaic account of creation.
The foundation of their conception was based upon Lin-
naeus' words: "There are as many different species as there
were different forms created in the beginning by the Infinite
Being." We must here remark at once, without going
further into the definition of species, that all zoologists and
botanists in their classificatory systems, in the practical dis-
tinction and designation of species of animals and plants,
never troubled, or even could trouble, themselves in the
slightest degree about this assumed creation of the parent
forms. In reference to this, one of our first zoologists, the
ingenious Fritz Mliller, makes the following striking obser-
vation : " Just as in Christian countries there is a catechism
of morals, which every one knows by heart, but which no
one considers it his duty to follow, or expects to see foUowed
by others, — so zoology also has its dogmas, which are just
as generally professed as they are denied in practice."
(Fiir Darwin, p. 71.) ^^

Linnaeus' venerated dogma of species is just such an
irrational dogma, and for that very reason it is powerful.
Although most naturalists blindly submitted to it, yet they
were, of course, never in a position to demonstrate the descent
of individuals belonging to one species from the common,
originally created, primitive form. Zoologists and botanists,
in their systems of nomenclature, confined themselves
entirely to the similarity of forms, in order to distinguish
and name the different species. They placed in one species

50 THE HISTORY OF CREATION.

all organic individuals wLicli were very similar, or almost
identical in form, and which could only be distinguished
from one another by very unimportant differences. On the
other hand, they considered as different species those
individuals which presented more essential or more striking
differences in the foiTQation of their bodies. But of course
this opened the flood-gates to the most arbitrary proceedings
in the systematic distinctions of species. For as all the
individuals of one species are never completely alike in
all their parts, but as every species varies more or less, no
one could point out which degree of variation constituted
a really " good species," or which degree indicated a "mere
variety.'*

This dogmatic conception of the idea of species, and
the arbitrary proceedings connected with it, necessarily
led to the most perplexing contradictions, and to the most
untenable suppositions. This is clearly demonstrable in
the case of the celebrated Cuvier (born in 1769), who
next to Linnseus has exercised the gTeatest influence on
the study of zoology. In his conception and definition of
the idea of species, he agreed on the whole with Linnseus,
and shared also his belief in an independent creation of
individual species. Cuvier considered their immutability
of such importance that he was led to the fooUsh asser-
tion— " The immutability of species is a necessary con-
dition of the existence of scientific natural history." As
Linnreus' definition of species did not satisfy him, he
made an attempt to give a more exact and, for syste-
matic practice, a more useful definition, in the following
words : ''' All those individual animals and plants belong to
one species which can be proved to be either descended

cuvier's definition of species. 51

from one another, or from common ancestors, or which are
as similar to these as the latter are among themselves."

In dealing with this matter, Cuvier reasoned in the
following manner: — "In those organic individuals, of which
we know that they are descended from one and the same
common form of ancestors — in which, therefore, their com-
mon ancestry is empirically proved — there can be no doubt
that they belong to one species, whether they differ much or
little from one another, or whether they are almost alike or
very unlike. Moreover, all those individuals also belong to
this species which differ no more from the latter (those
proved to be derived from a common stock) than these differ
from one another." In a closer examination of this definition
of species given by Cuvier, it becomes at once evident that
it is neither theoretically satisfactory nor practically appli-
cable. Cuvier, with this definition, began to move in the
same circle in which almost all subsequent definitions
of species have moved, through the assumption of -their
immutability.

Considering the extraordinary authority which George
Cuvier has gained in the science of organic nature, and in con-
sequence of the almost unlimited supremacy which his views
exercised in zoology, during the first half of our century, it
seems appropriate here to examine his influence a little more
closely. This is all the more necessary as we have to com-
bat, in Cuvier, the most formidable opponent to the Theory
of Descent and the monistic conception of nature.

One of the many and great merits of Cuvier is that he
stands forth as the founder of Comparative Anatomy. While
Linnaeus established the distinction of species, genera, orders,
and classes mostly upon external characters, and upon sepa-

52 THE HISTOEY OF CEEATION.

rate and easily discoverable signs in the number, size, place,
and form of individual organic parts of the body, Cuvier
penetrated much more deeply into the essence of organiza-
tion. He demonstrated great and wide differences in the
inner structure of animals, as the real foundation of a
scientific knowledge and classification of them. He dis-
tinguished natural families in the classes of animals, and
established his natural system of the animal kingdom on
their comparative anatomy.

The progress from Linnseus' artificial system to Cuvier's
natural system was exceedingly important. Linnaeus had
arranged all animals in a single series, which he divided
into six classes, two classes of Invertebrate, and four classes
of Vertebrate animals. He distinguished these artificially,
according to the nature of their blood and heart. Cuvier,
on the other hand, showed that in the animal kingdom there
were four great natural divisions to be distinguished, which
he termed Principal Forms, or General Plans, or Branches
of the animal kingdom (Embranchments), namely — 1. The
Vertebrate animals ( Vertebra ta) ; 2. The Articulate animals
(Articulata) ; 3. The Molluscous animals (Mollusca) ; and 4.
The Radiate animals (Radiata). He further demonstrated
that in each of these four branches a peculiar plan of struc-
ture or type was discernible, distinguishing each branch
from the three others. In the Vertebrate animals it is dis-
tinctly expressed by the form of the skeleton, or bony
framework, as also by the structure and position of the
dorsal nerve-chord, apart from many other peculiarities.
The Articulate animals are characterized by their ventral
nerve-chord and their dorsal heart. In Molluscs the sack-
shaped and non-articulate body is the distinguishing feature.

CUVIER AND BAER. 53

The Radiate animals, finally, differ from tlie three other
principal forms by their body being the combination of fonr
or more main sections united in the form of radii (antimera).

The distinction of these four principal forms of animals,
which has become extremely productive in the development
of zoology, is commonly ascribed entirely to Cuvier. How-
ever, the same thought was expressed almost simultaneously,
and independently of Cuvier, by Bar, one of the greatest
naturalists, and still living, who did the most eminent service
in the study of animal development. Bar showed that in the
development of animals, also, four different main forms (or
types) must be distinguished. ^^ These correspond with
the four plans of structure in animals, which Cuvier distin-
guished on the ground of comparative anatomy. Thus, for
example, the individual development of all Vertebrate ani-
mals agrees, from the commencement, so much in its funda-
mental features that the germs or embryos of different
Vertebrate animals (for example, of reptiles, birds, and
mammals) in their earlier stages cannot be distinguished at
all. It is only at a late stage of development that there
gradually appear the more marked differences of form which
separate those different classes and orders from one another.
The plan of structure, which shows itself in the individual
development of Articulate animals (insects, spiders, crabs),
is from the beginning essentially the same in all Articulate
animals, but different from that of all Vertebrate animals.
The same holds good, with certain limitations, in Molluscous
and Radiated animals.

Neither Bar, who arrived at the distinction of the four
animal types or principal forms through the history of the
individual development (Embryology), nor Cuvier, who
4

54 THE HISTORY OF CREATION.

arrived at the same conclusion by means of comparative
anatomy, recognized the true cause of this difierence.
This is disclosed to us by the Theory of Descent. The
wonderful and astonishing similarity in the inner organ-
ization and in the anatomical relations of structure, and
the still more remarkable agreement in the embryonic de-
velopment of all animals belonging to one and the same
type (for example, to the branch of the Vertebrate animals),
is explained in the simplest manner by the supposition of
their common descent from a single primary original form.
If this view is not accepted, then the complete agreement of
the most different Vertebrate animals, in their inner struc-
ture and their manner of development, remains perfectly
inexplicable. In fact it can only be explained by the law of
inheritance.

Next to the comparative anatomy of animals and the
systematic zoology founded anew by it, it was specially to
the science of petrifactions, or Palaeontology, that Cuvier
rendered great service. We must draw special attention
to this, because these very palseontological views, and the
geological ideas connected with them, were held almost
universally in the highest esteem during the first half of
the present century, and caused the greatest hindrance to
the working out of a truly natural history of creation.

Petrifactions, the scientific study of which Cuvier pro-
moted at the beginning of our century in a most ex-
tensive manner, and established quite anew for the Verte-
brate animals, play one of the most important parts in the
" non-miraculous history of creation." For these remains
and impressions of extinct animals and plants, preserved to
us in a petrified condition, are the true " monuments of the

FOSSIL ORGANISMS. 55

creation/' the infallible and indisputable records wliicb fix
the correct history of organisms upon an irrefragable founda-
tion. All petrified or fossil remains and impressions tell us
of the forms and structure of such animals and plants as are
either the progenitors and ancestors of the present living
organisms, or they are the representatives of extinct colla-
teral lines, which, together with the present living organisms,
branched ofi" from a common stem.

These inestimable records of the history of creation
throughout a long period played a subordinate part in
science. Their true nature was indeed correctly understood,
even more than five hundred years before Christ, by the
great Greek philosopher, Xenophanes of Colophon, the same
who founded the so-called Eleatic philosophy, and who was
the first to demonstrate with convincing precision that all
conceptions of personal gods result in more or less rude
anthropomorphism.

Xenophanes for the first time asserted that the fossil im-
pressions of animals and plants were real remains of formerly
living creatures, and that the mountains in whose rocks
they were found must at an earlier date have stood under
water. But although other great philosophers of antiquity,
and among them Aristotle, also possessed this true know-
ledge, yet throughout the illiterate Middle Ages, and even
with some naturalists of the last century, the idea prevailed
that petrifactions were so-called freaks of nature (lusus
naturae), or products of an unknown formative power or
instinct of nature (nisus formativus, vis plastica). Respect-
ing the nature of this mysterious and mystic creative
power, the strangest ideas were formed. Some believed that
this constructive power — the same to which they also

56 THE HISTORY OF CKEATION.

ascribed the coming into existence of the present species of
animals and plants — had made numerous attempts to create
organisms of different forms, but that these attempts had
only partially succeeded, had often failed, and that petrifac-
tions were nothing more than such unsuccessful attempts.
According to others, petrifactions originated from the in-
fluence of the stars upon the interior of the earth.

Others, again, had the still cruder notion that the Creator
had first made models (out of mineral substances — for
example, of gypsum or clay) of those forms of animals and
plants which he afterwards executed in organic substances,
and into which he breathed his living breath ; petrifactions
were accordingly such rude inorganic models. Even as late
as the last century these crude ideas prevailed, and it was
assumed, for example, that there existed a special " seminal
air," which was said to penetrate into the earth with
the water, and by fructifying the stones formed petrifactions
or " stony flesh " (caro fossilis).

It took a very long time before the simple and natural
view was accepted, namely, that petrifactions are in reality
nothing but what they appear to simple observation — the
indestructible remains of extinct organisms. It is true the
celebrated painter, Leonardo da Vinci, in the 15th century,
ventured to assert that the mud which was constantly
deposited by water was the cause of petrifactions, as it
surrounded the indestructible shells of mussels and snails
which lay at the bottom of the waters, and gradually turned
them into solid stone. The same idea was maintained in
the IGth century by a Parisian potter, Palissy by name,
who became celebrated on account of his invention of
china. However, the so-called " professional men " were

cuvier's work in paleontology. 57

very far from paying any regard to these correct assertions
of a simple and healthy human understanding; it was
not till the end of the last century that it was generally
accepted, in consequence of the foundation of the Neptunian
geology by Werner.

The foundation of a more strictly scientific palaeontology,
however, belongs to the beginning of our century, when
Cuvier published his classic researches on petrified Verte-
brate animals, and when his great opponent, Lamarck, made
known his remarkable investigations on fossil Invertebrate
animals, especially on petrified snails and clams. In Cuvier's
celebrated work "On the Fossil Bones" of Vertebrate animals
— principally of mammals and reptiles — we see that he had
already arrived at the knowledge of some very important
and general paleeontological laws, which are of great con-
sequence to the history of creation. Foremost among them
stands the assertion that the extinct species of animals,
whose remains we find petrified in the difierent strata of
the earth's crust, lying one above another, difier all the
more strikingly from the still living kindred species
of animals the deeper those strata lie — in other words, the
earlier the animals lived in past ages. In fact, in every per-
pendicular section of the stratified crust of the earth we
find that the difierent strata, deposited by the water in a
certain historical succession, are characterized by different
petrifactions, and that these extinct organisms become more
like those of the present day the higher the strata lie ; in
other words, the more recent the period in the earth's
history in which they lived, died, and became encrusted by
the deposited and hardened strata of mud.

However important this general observation of Cuvier's

58 THE HISTORY OF CREATION.

was in one sense, yet in another it became to him the source
of a very serious error. For as he considered the charac-
teristic petrifactions of each individual group of strata
(which had been deposited during one main period of the
earth's history) to be entirely different from those of the
strata lying above or below, and as he erroneously believed
that one and the same species of animal was never found in
two succeeding groups of strata, he arrived at the false idea,
which was accepted as a law by most subsequent naturalists,
that a series of quite distinct periods of creation had
succeeded one another. Each period was supposed to have
had its special animal and vegetable world, each its peculiar
specific Fauna and Flora.

Cuvier imagined that the whole history of the earth's
crust, since the time when living creatures had fiirst appeared
on the surface, must be divided into a number of perfectly
distinct periods, or divisions of time, and that the individual
periods must have been separated li'om one another by
peculiar revolutions of an unknown nature (cataclysms, or
catastrophes). Each revolution was followed by the utter
annihilation of the till then existing animals and plants, and
after its termination a completely new creation of organic
forms took place. A new world of animals and plants,
absolutely and specifically distinct from those of the preced-
ing historical periods, was called into existence at once, and
now again peopled the globe for thousands of years, till it
again perished suddenly in the crash of a new revolution.

About the nature and causes of these revolutions, Cuvier
expressly said that no idea could be formed, and that the
present active forces in nature were not sufficient for their
explanation. Cuvier points out four active causes as the

cuvier's cataclysms. 59

natural forces, or mechanical agents, at present constantly
but slowly at work in changing the earth's surface : first,
rain, which washes down the steep mountain slopes
and heaps up debris at their foot; secondly, flowing
waters, which carry away this debris and deposit
ii as mud in stagnant waters ; thirdly, the sea, whose
bieakers gnaw at the steep sea coasts, and throw up
" dunes " on the flat sea margins ; finally and fourthly,
vdcanos, which break through and heave up the strata of
the earth's hardened crust, and pile up and scatter about the
products of their eruptions. Whilst Cuvier recognizes the
constant slow transformation of the present surface of the
earth by these four mighty causes, he asserts at the same
time that they would not have sufficed to effect the
revolutions of the remote ages, and that the anatomical
structure of the earth's surface cannot be explained by
the necessary action of those mechanical agents : the great
and marvellous revolutions of the whole earth's surface
must, according to him, have been rather the effects of very
peculiar causes, completely unknown to us ; the usual thread
of development was broken by them, and the course of
nature altered.

These views Cuvier explained in a special work " On the
Revolutions of the Earth's Surface, and the Changes which
they have wrought in the Animal World." They were
maintained, and generally accepted for a long time, and be-
came the greatest obstacle to the development of a natural
history of the creation. For if such all-destructive revolu-
tions had actually occurred, of course a continuity of the
development of species, a connecting thread in the organic
history of the earth, could not be admitted at all, and we

6o THE HISTORY OF CREATION.

should be obliged to bave recourse to the action of super-
natural forces ; tbat is, to tlie interference of miracles in the
natural course of things. It is only through miracles that
these revolutions of the earth could have been brought about,
and it is only through miracles that, after their cessation
and at the commencement of each new period, a new animal
and vegetable kingdom could have been created. But
science has no room for miracles, for by miracles we under-
stand an interference of supernatural forces in the naturxl
course of development of matter. '

Just as the great authority which Linnseus gained by
his system of distinguishing and naming organic species
led his successors to a complete ossification, as it were, of the
dogmatic idea of species and to a real abuse of the syste-
matic distinction implied by it, so the great services which
Cuvier had rendered to the knowledge and distinction
of extinct species became the ca^use of a general adoption
of his theory of revolutions and catastrophes, and of the
false views of creation connected therewith. The conse-
quence of this was that, during the first half of our century,
most zoologists and botanists clung to the opinion that a
series of independent periods in the organic history of the
earth had existed ; that each period was distinguished by
distinct and peculiar kinds of animal and vegetable species ;
that these were annihilated at the termination of the period
by a general revolution ; and that, after the cessation of the
latter, a new world of different species of animals and plants
was created.

It is true some independent thinkers, above all the great
physical philosopher, Lamarck, even at an early period, set
forth a series of weighty reasons which refuted Cuvier's

AGASSIZ ON CEEATION. 6 1

theory of cataclysms, and pointed to a perfectly continuous
and uninterrupted developmental history of all the organic
inhabitants of the earth through all ages. They maintained
that the animal and vegetable species of each period were
derived from those of the preceding period, and were only
the altered descendants of the former. This true conception,
however, being opposed to Cuvier's great authority, was
then unable to make way. Nay, even after Cuvier's theory
of catastrophies had been completely cast out from the
domain of geology by Lyell's classic Principles of Geology,
which appeared in 1830, still his idea of the specific dis-
tinctness of a series of organic creations maintained its
influence, in many ways, in the science of Palaeontology.
(Gen. Morph. ii. 312.)

By a curious coincidence, thirteen years ago, almost at
the same time that Cuvier's History of Creation received its
death-blow by Darwin's book, another celebrated naturalist
made an attempt to re-establish it, and to adopt it in the
roughest manner, as a part of a teleologico-theological
system of nature. This was the Swiss geologist, Louis
Agassiz, who attained a great reputation by his theory
of glaciers and the ice-period, borrowed from Schimper and
Charpentier, and who has been living in North America for
many years. He commenced in 1858 to publish a work
planned on a very large scale, which bears the title of
" Contributions to the Natural History of the United States
of North America." The first volume of this work, although
large and costly, owing to the patriotism of the Americans,
had an unprecedented sale ; its title is, " An Essay on Classi-
fication." ^

In this essay Agassiz not only discusses the natural series

62 THE HISTOEY OF CREATION.

of organisms, and the different attempts of naturalists at
classification, but also all the general biological phenomena
which have reference to it. The history of the development
of organisms, both the embryonal and the palseontological,
comparative anatomy, the general economy of nature, the
geographical and topographical distribution of animals and
plants — in short, almost all the general phenomena of
organic nature are discussed in Agassiz's Essay on Classifi-
cation, and are explained in a sense and from a point of
view which is thoroughly opposed to that of Darwin.
While Darwin's chief merit lies in the fact that he demon-
strates natural causes for the coming into existence of
animal and vegetable species, and thereby establishes the
mechanical or monistic view of the universe as regards this

o

most difficult branch of the history of creation, Agassiz, on
the contrary, strives to exclude every mechanical hypothesis
from the subject, and to put the supernatural interference
of a personal Creator in the place of the natural forces
of matter ; consequently, to establish a thoroughly teleo-
logical or dualistic view of the universe. It will not be
out of place if I examine a little more closely Agassiz's
biological views, and especially his ideas of creation,
because no other work of onr opponents treats the important
fundamental questions with equal minuteness, and because
the utter untenableness of the dualistic conception of nature
becomes very evident from the failure of this attempt.

The organic species, the various conceptions of which we
have above designated as the real centre of dispute in the
opposed views of creation, is looked upon by Agassiz, as
by Cuvier and Linnseus, as a form unchangeable in all its
essential characteristics. The species may indeed change

A.GASSIZ ON CREATION. 63

and vary witliin certain narrow limits ; never in essential
qualities, but only in unessential points. No new species
could ever proceed from the changes or varieties of a species.
Not one of all organic species, therefore, is ever derived from
another, but each individual species has been separately
created by God. Each individual species, as Agassiz
expresses it, is " an embodied creative thought " of God.

In direct opposition to the fact established by palseonto-
logical experience, that the duration of the individual
organic species is most unequal, and that many species
continue unchanged through several successive periods of
the earth's history, while others only existed during a small
portion of such a period, Agassiz maintains that one and
the same species never occurs in two different periods, but
that each individual period is characterized by species of
animals and plants which are quite peculiar, and belong to
it exclusively. He further shares Cuvier's opinion that the
whole of these inhabitants were annihilated by the great
and universal revolutions of the earth's surface, which
divide two successive periods, and that after its destruction
a new and specifically different assemblage of organisms was
created. This new creation Agassiz supposes to have taken
place in this manner : viz., that at each creation all the
inhabitants of the earth, in their full average number of
individuals, and in the peculiar relations corresponding
to the economy of nature, were, as a whole, suddenly placed
upon the earth by the Creator. In saying this he puts
himself in opposition to one of the most firmly established
and most important laws of animal and vegetable geography
— namely, to the law that each species has a single original
locality of origin, or a so-called " centre of creation," from

64 THE HISTORY OF CEEATION.

wliicli it has gradually spread over the rest of the earth.
Instead of this, Agassiz assumes each species to have been
created at several points of the earth's surface, and that in
each case a large number of individuals was created.

The " natural system " of organisms, the different groups
and categories of which arranged above one another —
namely, the branches, classes, orders, families, genera, and
species — we consider, in accordance with the Theory of
Descent, as different branches and twigs of the organic family-
tree, is, according to Agassiz, the direct expression of the
divine plan of creation, and the naturalist, while investigat-
ing the natural system, repeats the creative thoughts of God.
In this Agassiz finds the strongest proof that man is the
image and child of God. The different stages of groups or
categories of the natural system correspond with the different
stages of development which the divine plan of creation
had attained. The Creator, in projecting and carrying out
this plan, starting from the most general ideas of creation,
plunged more and more into specialities. For instance,
when creating the animal kingdom, God had in the first
place four totally distinct ideas of animal bodies, which he
embodied in the difierent structures of the four great,
principal forms, types, or branches of the animal kingdom;
namely, vertebrate animals, articulate animals, molluscous
animals, and radiate animals. The Creator then, having
reflected in what manner he might vary these four different
plans of structure, next created within each of the four
principal forms, several different classes — for example, in
the vertebrate animal form, the classes of mammals,
birds, reptiles, amphibious animals, and fishes. Then
God further reflected u[)on the individual classes, and by

THE CREATOR AS AN ARCHITECT. 65

various modifications in the structure of each class, he pro-
duced the individual orders. By further variation in the
order, he created natural families. As the Creator further
varied the peculiarities of structure of individual parts in
each family, genera arose. In further meditation on his
plan of creation, he entered so much into detail that in-
dividual species came into existence, which, consequently,
are embodied creative thoughts of the most special kind.
It is only to be regretted that the Creator expressed these
most special and most deeply considered "creative thoughts"
in so very indistinct and loose a manner, and that he im-
printed so vague a stamp upon them, and permitted them to
vary so freely that not one naturalist is able to distinguish
the "good" from the "bad species," or a genuine species
from varieties, races, etc. (Gen. Morph. ii. 373.)

We see, then, according to Agassiz's conception, that the
Creator, in producing organic forms, goes to work exactly
as a human architect, who has taken upon himself the task
of devising and producing as many different buildings as
possible, for the most manifold purposes, in the most dif-
ferent styles, in various degrees of simplicity, splendour,
greatness, and perfection. This architect would perhaps at
first choose four difierent styles for all these buildings, say
the Gothic, Byzantine, Chinese, and Rococo styles. In each
of these styles he would build a number of churches, palaces,
garrisons, prisons, and dwelling-houses. Each of these dif-
ferent buildings he would execute in ruder and more perfect,
in greater and smaller, in simpler and grander fashion, etc.
However, the human architect would perhaps, in this
respect, be better off than the divine Creator, as he would
have perfect liberty in the number of graduated subordinate

66 THE HISTORY OF CREATION.

groups. The Creator, however, according to Agassiz, can
only move within six groups or categories : the species,
genus, family, order, class, and type. More than these six
categories do not exist for him.

When we read Agassiz's book on classification, and see
how he carries out and establishes these strange ideas, we can
scarcely understand how, with all the appearance of scien-
tific earnestness, he can persevere in his idea of the divine
Creator as a man-like being (anthropomorphism), for by his
explanation of details he produces a picture of the most
absurd nonsense. In the whole series of these suppositions
the Creator is nothing but an all-mighty man, who, plagued
with ennui, amuses himself with planning and constructing
most varied toys in the shape of organic species. After
having diverted himself with these for thousands of years,
they become tiresome to him, he destroys them by a general
revolution of the earth's surface, and thus throws the whole
of the useless toys in heaps together; then, in order to
while away his time with something new and better, he
calls a new and more perfect animal and vegetable world
into existence. But in order not to have the trouble of
beginning the work of creation over again, he keeps, in the
main, to his original plan of creation, and creates merely
new species, or at most only new genera, and much more
rarely new families, new orders, or classes. He never suc-
ceeds in producing a new style or type, and always keeps
strictly within the six categories or graduated groups.

When, according to Agassiz, the Creator has thus amused
himself for thousands of millions of years with constructing
and destroying a series of difierent creations, at last (but
very late) he is struck with the happy thought of creating

INCONSISTENCY OF AGASSIZ. 67

something like himself, and so makes man in his own image.
The end of all the history of creation is thus arrived at
and the series of revolutions of the earth is closed. Man,
the child and image of God, gives him so much to do, causes
him so much pleasure and trouble, that he is wearied no
longer, and therefore need not undertake a new creation.
It is clear that if, according to Agassiz, we once assign
to the Creator entirely human attributes and qualities, and
regard his work of creation as entirely analogous to human
creative activity, we are necessarily obliged to admit such
utterly absurd inferences as those just stated.

The many intrinsic contradictions and perversities in
Agassiz's view of creation — a view which necessarily led
him to the most decided opposition to the Theory of
Descent — ^must excite our astonishment all the more be-
cause, in his earlier scientific works, he had in many
respects actually paved the way for Darwin, especially
by his researches in Palaeontology. Among the numerous
investigations which created general interest in the then
young science of Palaeontology, those of Agassiz, especially
his celebrated work on " Fossil Fish," rank next in import-
ance to Cuvier's work, which formed the foundation of the
science. The petrified fish, with which Agassiz has made
us acquainted, have not only an extremely great import-
ance for the understanding of all groups of Vertebrate
animals, and their historical development, but we have
arrived through them at a sure knowledge of important
general laws of development, some of which were first
discovered by Agassiz. He it was who drew special atten-
tion to the remarkable parallelism between the embryonal
and the palseontological development — between ontogeny

68 THE HISTORY OF CREATION.

and phylogeny, which I have abeady (p. 10) claimed as
one of the strongest pillars of the Theory of Descent. No
one before had so distinctly stated as Agassiz did, that, of
the Vertebrate animals, fishes alone existed, at first, that
amphibious animals came later, and that birds and mam-
mals appeared only at a much later period, further, that
among mammals, as among fishes, imperfect and lower
orders had appeared first, but more perfect and higher
orders at a later period. Agassiz, therefore, showed that
the palseontological development of the whole Vertebrate
group was not only parallel with the embryonic, but also
with the systematic development, that is, with the gi^aduated
series which we see everywhere in the system, ascending
from the lower to the higher classes, orders, etc.

In the earth's history lower forms appeared first, the
higher forms later. This important fact, as well as the
agTeement of the embryonic and palaeontological develop-
ment, is explained quite simply and naturally by the
Doctrine of Descent, and without it is perfectly inex-
plicable. This cause holds good also in the great law of
'progressive development, that is, of the historical progress
of organization, which is traceable, broadly and as a whole,
in the historical succession of all organisms, as well as in
the special perfecting of individual parts of animal bodies.
Thus, for example, the skeleton of Vertebrate animals
acquired at first slowly, and by degrees, that high degree
of perfection which it now possesses in man and the other
higher Vertebrate animals. This progress, acknowledged
in point of fact by Agassiz, necessarily follows from Dar-
win's Doctrine of Descent, which demonstrates its active
causes. If this doctrine is correct, the perfecting and diver-

DEVELOPMENT OF THE CREATOE. 69

sification of animal and vegetable species must of necessity
have gradually increased in the course of the organic history
of the earth, and could only attain its highest perfection in
most recent times.

The above-mentioned laws of development, together with
some other general ones, which have been expressly admitted
and justly emphasized by Agassiz, and some of which have
first been set forth by him, are, as we shall see later, only
explicable by the Theory of Descent, and without it remain
perfectly incomprehensible. The conjoint action of In-
heritance and Adaptation, as explained by Darwin, can
alone be their true cause. But they all stand in sharp and
irreconcilable opposition to the hypothesis of creation main-
tained by Agassiz, as well as to the idea of a personal
Creator who acts for a definite purpose. If we seriously
wish to explain those remarkable phenomena and their
inter-connection by Agassiz's theory, then we are necessarily
driven to the curious supposition that the Creator himself
has developed, together with the organic nature which he
created and modelled. We can, in that case, no longer rid
ourselves of the idea that the Creator himself, like a human
being, designed, improved, and finally, with many altera-
tions, carried out his plans. " Man grows as higher grow
his aims," and the same supposition, so unworthy of a God,
must be applied to him. Although, from the reverence
with which, in every page, Agassiz speaks o± the Creator,
it might appear that, on his theory, we attain to the
sublimest conception of the divine activity in nature, yet
the contrary is in truth the case. The divine Creator is
degi'aded to the level of an idealized man, of an organism
progressing in development ! '

70 THE HISTORY OF CREATION.

Considering the wide popularity and great authority
which Agassiz's work has gained, and which is perhaps
justified on account of earlier scientific services rendered by
the author, I have thought it my duty here to show the
utter untenableness of his general conceptions. So far as
this work pretends to be a scientific history of creation, it
is undoubtedly a complete failure. But still it has great
value, being the only detailed attempt, adorned with scien-
tific arguments, which an eminent naturalist of our day
has made to found a teleological or dualistic history of
creation. The utter impossibility of such a history has
thus been made obvious to every one. No opponent of
Agassiz could have refuted the dualistic conception of
organic nature and its origin more strikingly than he him-
self has done by the intrinsic contradictions which present
themselves everywhere in his theory.

The opponents of the monistic or mechanical conception
of the world have welcomed Agassiz's work with delight,
and find in it a perfect proof of the direct creative action of
a personal God. But they overlook the fact that this per-
sonal Creator is only an idealized organism, endowed with
human attributes. This low dualistic conception of God
corresponds with a low animal stage of development of
the human organism. The more developed man of the pre-
sent day is capable of, and justified in, conceiving that
infinitely nobler and sublimer idea of God which alone is
compatible with the monistic conception of the universe, and
which recognizes God's spirit and power in all phenomena
without exception. This monistic idea of God, which belongs
to the future, has already been expressed by Giordano
Bruno in the following words: — "A spirit exists in all

UNITY OF GOD AND NATUEE. 71

things, and no body is so small but contains a part of the
divine substance within itself, by which it is animated." It
is of this noble idea of God that Goethe says : — " Certainly
there does not exist a more beautiful worship of God than
that which needs no image, but which arises in our heart
from converse with Nature." By it we arrive at the sublime
idea of the Unity of God and NaturOi

72 THE HISTORY OF CREATION.

CHAPTER IV.

THEORY OF DEVELOPMENT ACCORDING TO GOETHE

AND 0IO]N.

Scientific Insufficiency of all Conceptions of a Creation of Individnal Species
— Necessity of the Counter Theories of Development. — Historical
Survey of the Most Important Theories of Development. — Aristotle. —
His Doctrine of Spontaneous Generation. — The Meaning of Natural
Philosophy. — Goethe. — His Merits as a Naturalist. — His Metamorphosis
of Plants. — His Yertebral Theory of the Skull. — His Discovery of the
Mid Jawbone in Man. — Goethe's Interest in the Dispute between
Cuvier and Geoffrey St. Hilaire. — Goethe's Discovery of the Two Organic
Formative Principles, of the Conservative Principle of Specification (by
Inheritance), and of the Progressive Principle of Transformation (by
Adaptation). — Goethe's Yiews of the Common Descent of aU Yertebrate
Animals, including Man. — Theory of Development according to Gottfried
Reinhold Treviranus. — His Monistic Conception of Nature. — Oken. — His
Natural Philosophy, — Oken's Theory of Protoplasm. — Oken's Theory
of Infusoria (Cell Theory). — Oken's Theory of Development.

All tlie different ideas which we may form of a separate
and independent origin of the individual organic species
by creation lead us, when logically carried out, to a so-
called anthropomorphism, that is, to imagining the Creator
as a man-like being, as was shown in our last chapter.
The Creator becomes an organism who designs a plan,
reflects upon and varies this plan, and finally forms
creatiu-es according to this plan, as a human architect
would his building. If even such eminent natm^alists as

FAILURE OF TELEOLOGY. 73

Linnaeus, Cuvier, and Agassi z, the principal representatives
of the dualistic hypothesis of creation, could not arrive at a
more satisfactory view, we may take it as evidence of the
insufficiency of all those conceptions which would derive
the various forms of organic nature from a creation of
individual species.

Some naturalists, indeed, seeing the complete insuffi-
ciency of these views, have tried to replace the idea of a
personal Creator by that of an unconsciously active and
creative Force of Nature ; yet this expression is evidently
merely an evasive phrase, as long as it is not clearly shown
what this force of nature is, and how it works. Hence
these attempts, also, have been absolute failures. In fact,
whenever an independent origin of the different forms of
animals and plants has been assumed, naturalists have
fomid themselves compelled to fall back upon so many "acts
of creation," that is, on supernatural interferences of the
Creator in the natural course of things, which in all other
cases goes on without interference.

It is true that several teleological naturalists, feeling
the scientific insufficiency of a supernatural " creation !'
have endeavoured to save the hypothesis by wishing it to
be understood that creation "is nothing else than a way of
coming into being, unknown and inconceivable to us." The
eminent Fritz Miiller has cut off from this sophistic evasion
every chance of escape by the following striking remark : —
" It is intended here only to express in a disguised manner
the shamefaced confession, that they neither have, nor care
to have, any ojpinion about the origin of species. Accord-
ing to this explanation of the word, we might as well speak
of the creation of cholera, or syphilis, of the creation of a

74 THE HISTORY OF CREATION.

conflagration, or of a railway accident, as of the creation of
man." (Jenaische Zestscrift, bd. v. p. 272.)

In the face, then, of these hypotheses of creation, which
are scientifically insufficient, we are forced to seek refuge in
the counter-theory of development of organisms, if we wish
to come to a rational conception of the origin of organ-
isms. We are forced and obliged to do so, even if the theory
of development only throws a glimmer of probability
upon a mechanical, natural origin of the animal and vege-
table species; but all the more if, as we shall see, this
theory explains all facts simply and clearly, as well as com-
pletely and comprehensively. The theories of develop-
ment are by no means, as they often falsely are represented
to be, arbitrary fancies, or wilful products of the imagination,
which only attempt approximately to explain the origin of .
this or that individual organism; but they are theories
founded strictly on science, which explain in the simplest
manner, from a fijced and clear point of view, the whole of
organic natural phenomena, and more especially the origin
of organic species, and demonstrate them to be the necessary
consequences of mechanical processes in nature.

As I have already shown in the second chapter, all
these theories of development coincide naturally with that
general theory of the universe which is usually designated
as the uniform or monistic, often also as the mechanical or
causal, because it only assumes mechanical causes, or causes
working by necessity (causae efficientes), for the explanation
of natural phenomena. In like manner, on the other hand,
the supernatural hypotheses of creation which we have al-
ready discussed coincide completely with the opposite view
of the universe, which in contrast to the former is called the

THE THEORY OF DESCENT. 75

twofold or dualistic, often the teleological or vital, because
it traces the organic natural phenomena to final causes,
acting and tuorJcing for a definite purpose (causse finales).
It is this deep and intrinsic connection of the difierent
theories of creation with the most important questions of
philosophy that incites us to their closer examination.

The fundamental idea, which must necessarily lie at the
bottom of all natural theories of development, is that of a
gradual development of all (even the most perfect) or-
ganisms out of a single, or out of a very few, quite simple,
and quite imperfect original beings, which came into exist-
ence, not by supernatural creation, but by spontaneous
generation, or archigony, out of inorganic matter. In
reality, there are two distinct conceptions united in this
fundamental idea, but which have, nevertheless, a deep in-
trinsic connection — namely, first, the idea of spontaneous
generation (or archigony) of the original primary beings ;
and secondly, the idea of the progressive development of
the various species of organisms from those most simple
primary beings. These two important mechanical concep-
tions are the inseparable fundamental ideas of every theory
of development, if scientifically carried out. As it maintains
the derivation of the different species of animals and plants
from the simplest, common primary species, we may term
it also the Doctrine of Filiation, or Theory of Descent; as
there is also a change of species connected with it, it may
also be termed the Transmutation Theory.

While the supernatural histories of creation must have
originated thousands of years ago, in that very remote
primitive age when man, first developing out of the monkey-
state, began for the first time to think more closely about

76 THE HISTORY OF ^CREATION.

himself, and about the origin of the world around him, the
natural theories of development, on the other hand, are
necessarily of much more recent origin. These views are
met with only among nations of a more matured civilization,
to whom, by philosophic culture, the necessity of a know-
ledge of natural causes has become apparent; and even among
these, only individual and specially gifted natures can be
expected to have recognized the origin of the world of
phenomena, as well as its course of development, as the
necessary consequences of mechanical, naturally active
causes. In no nation have these preliminary conditions, for
the origin of a natural theory of development, ever existed
in so high a degree as among the Greeks of classic antiquity.
But, on the other hand, they lacked a close acquaintance
with the facts of the processes and forms of nature, and,
consequently, the foundation based upon experience, for a
satisfactory unravelling of the problem of development.
Exact investigation of nature, and the knowledge of nature
founded on an experimental basis, was of course almost
unknown to antiquity, as well as to the Middle Ages, and
is only an acquisition of modern times. We have therefore
here no special occasion to examine the natural theories
of development of the various Greek philosophers, since
they were wanting in the knowledge gained by experience,
both of organic and inorganic nature, and since they
almost always, as the consequence, lost themselves in airy
speculations.

One man only must be mentioned here by way of
exception, — Aristotle, the greatest and the only truly great
naturalist of antiquity and the Middle Ages, one of the
grandest geniuses of all time. To what a degree he stands

ARISTOTLE ON THE ORIGIN OF LIFE. ']']

there alone, during a period of more than two thousand
years, in the region of empirico-philosophical knowledge of
nature, and especially in his knowledge of organic nature, is
proved to us by the precious remains of his but partially
surviving works. In them many traces are found of a
theory of natural development. Aristotle assumes, as a
matter of certainty, that spontaneous generation was the
natural manner in which the lower organic creatures came
into existence. He describes animals and plants originating
from matter itself, through its own original force ; as, for
example, moths from wool, fleas from putrid dung, wood-lice
from damp wood, etc. But as the distinction of organic
species, which Linnseus only arrived at two thousand years
later, was unknown to him, he could form no ideas about
their genealogical relations.

The fundamental notion of the theory of development,
that the different species of animals and plants have been
developed from a common primary species by transformation,
could of course only be clearly asserted after the kinds oi
species themselves had become better known, and after the
extinct species had been carefully examined and compared
with the living ones. This was not done until the end
of the last and the beginning of the present century.
It was not until the year 1801 that the great Lamarck
expressed the theory of development, which he, in 1809,
further elaborated in his classical " Philosophic Zoologique."
While Lamarck and his countryman, Geoffroy St. Hilaire, in
France, opposed Cuvier's views, and maintained a natural
development of organic species by transformation and
descent, Goethe and Oken at the same time pursued the
same course in Germany, and helped to establish the theory

jS THE HISTORY OF CREATION.

of development. As these naturalists are generally called
nature-philosophers (Naturphilosophen), and as this
ambiguous designation is correct in a certain sense, it
appears to me appropriate here to say a few words about
the correct estimate of the " Naturphilosophie."

Although for many years in England the ideas of natural
science and philosophy have been looked upon as almost
equivalent, and as every truly scientific investigator of
nature is most justly called there a " natural philosopher,"
yet in Germany for more than half a century natural science
has been kept strictly distinct from philosophy, and the union
of the two into a true philosophy of nature is recognized
only by the few. This misapprehension is owing to the
fantastic eccentricities of earlier German natural-philosophers,
such as Oken, Schelling, etc. ; they believed that they were
able to construct the laws of nature in their own heads,
without being obliged to take their stand upon the grounds
of actual experience. When the complete hollowness of
their assumptions had been demonstrated, naturalists, in
"the nation of thinkers," fell into the very opposite extreme,
believing that they would be able to reach the high aim of
science, that is, the knowledge of truth, by the mere experi-
ence of the senses, and without any philosophical activity of
thought.

From that time, but especially since 1830, most natiu'alists
have shown a strong aversion to any general, philosophical
view of nature. The real aim of natural science was now
supposed to consist in the knowledge of details, and it was
believed that this would be attained in the study of biology,
when the forms and the phenomena of life, in all individual
organisms, had become accurately known, by the help of the

OBSERVATION ANI> REFLECTION. 79

finest instruments and means of observation. It is true that
among these strictly empirical, or so-called exact naturalists,
there were always very many who rose above this narrow
point of view, and sought the final aim in a knowledge of
the general laws of organization. Yet the great majority of
zoologists and botanists, during the thirty or forty years
preceding Darwin, refused to concern themselves about such
general laws; all they admitted was, that perhaps in the far
distant future, when the end of all empiric knowledge should
have been arrived at, when all individual animals and plants
should have been thoroughly examined, naturalists might
begin to think of discovering general biological laws.

If we consider and compare the most important advances
which the human mind has made in the knowledge of
truth, we shall soon see that it is always owing to philo-
sophical mental operations that these advances have been
made, and that the experience of the senses which certainly
and necessarily precedes these operations, and the knowledge
of details gained thereby, only furnish the basis for those
general laws. Experience and philosophy, therefore, by no
means stand in such exclusive opposition to each other as
most men have hitherto supposed ; they rather necessarily
supplement each other. The philosopher who is wanting in
the firm foundation of sensuous experience, of empirical
knowledge, is very apt to arrive at false conclusions in his
general speculations, which even a moderately informed
naturalist can refute at once. On the other hand, the purely
empiric naturalists, who do not trouble themselves about the
philosophical comprehension of their sensuous experiences,
and who do not strive after genei^l knowledge, can promote
science only in a very slight degree, and the chief value of

So THE HISTOPtY OF CEEATION.

their hard-won knowledge of details lies in the general
results which more comprehensive minds will one day
derive from them.

From a general survey of the com^se of biological develop-
ment since Linngeus' time, we can easily see, as Bar has
pointed out, a continual vacillation between these two ten-
dencies, at one time a prevalence of the empirical — the
so-called exact — and then again of the philosophical or
speculative tendency. Thus at the end of the last century,
in opposition to Linnaeus' purely empirical school, a natural-
philosophical reaction took place, the moving spirits of
which, Lamarck, Geoffroy St. Hilaire, Goethe, and Oken,
endeavoured by their mental work to introduce light and
order into the chaos of the accumulated empirical raw
material. In opposition to the many errors and specu-
lations of these natural philosophers, who went too far,
Cuvier then came forward, introducing a second, purely
empirical period. It reached its most one-sided development
between the years 1830-1860, and there now followed a
second philosophical reaction, caused by Darwin's work.
Thus during the last ten years, men again have begun to
endeavour to obtain a knowledge of the general laws of
natiu'e, to which, after all, all detailed knowledge of experi-
ence serves only as a foundation, and through which alone
it acquires its true value. It is through philosophy alone
that natural knowledge becomes a true science, that is,
a philosophy of nature. (Gen. Morph. i. 63-108.)

Jean Lamarck and Wolfgang Goethe stand at the head of
all the gTeat philosophers of nature who first established a
theory of organic development, and who are the illustrious
fellow-workers of Darwin. I turn first to our beloved

GOETHE AS A NATURALIST. 8 1

Goethe, who, among all, stands in the closest relations to us
Germans. However, before I explain his special services
to the theory of development, it seems to me necessary
to say a few words about his importance as a naturalist in
general, as it is commonly very little known.

I am sure most of my readers honour Goethe only as a
poet and a man ; only a few have any conception of the high
value of his scientific works, and of the gigantic stride with
which he advanced before his own age — advanced so much
that most naturalists of that time were unable to follow
him. In several passages of his scientific writings he
bitterly complains of the narrow-mindedness of professed
naturalists, who do not know how to value his works (who
cannot see the wood for the trees), and who cannot rouse
themselves to discover the general laws of nature among the
mass of details. He is only too just when he utters the
reproach — "The philosophers will very soon discover that
observers rarely rise to a stand-point from which they can
survey so many important objects." It is true, at the same
time, that their want of appreciation was caused by the
false road into which Goethe was led in his theory of colours.
This theory of colours, which he himself designates as
the favourite production of his leisure, however much
that is beautiful it may contain, is a complete failure in
regard to its foundations. The exact mathematical method
by means of which alone it is possible, in inorganic
sciences, but above all in physics, to raise a structure
step by step on a thoroughly firm basis, was altogether re-
pugnant to Goethe. In rejecting it he allowed himself not
only to be very unjust towards the most eminent phy-
sicists, but to be led into errors which have greatly injured

S2 THE HISTOEY OF CPvEATlON.

the fame of his other valuable works. It is quite different
in the organic sciences, in which we are but rarely able to
proceed, from the beginning, upon a firm mathematical
basis; we are rather compelled, by the infinitely difficult
and intricate nature of the problem, at the first to form
inductions — that is, we are obliged to endeavour to establish
general laws by numerous individual observations, which
are not quite complete. A comparison of kindred series of
phenomena, or the method of combination, is here the most
important instrument for inquiry, and this method was
applied by Goethe with as much success as with conscious
knowledge of its value, in his works relating to the
philosophy of nature.

The most celebrated amongr Goethe's writinpjs relatinpf to
organic nature is his Metamorphosis of Plants, which ap-
peared in 1790, a work which distinctly shows a grasp of the
fundamental idea of the theory of development, inasmuch
as Goethe, in it, was labouring to point out a single organ,
by the infinitely varied development and metamorphosis of
which the whole of the endless variety of forms in the world
of plants might be conceived to have arisen; this funda-
mental organ he found in the leaf. If at that time the mi-
croscope had been generally employed, if Goethe had
examined the structure of organisms by the means of the
microscope, he would have gone still fui'ther, and would
have seen that the leaf is itself a compound of individual
parts of a lower order, that is, of cells. He would then not
have declared that the leaf, but that the cell is the real fun-
damental organ by the multiplication, transformation, and
combination (synthesis) of which, in the first place, the leaf
is formed ; and that, in the next place, by transformation,

Goethe's theory of the skull. S^

variation, and combination of leaves there arise all the
varied beauties in form and colour which we admire in the
green parts, as well as in the organs of propagation, or the
flowers of plants. Goethe here showed that in order to
comprehend the whole of the phenomena, we must in the
first place compare them, and, secondly, search for a simple
type, a simple fundamental form, of which all other forms
are only infinite variations.

Something similar to what he had here done for the meta-
morphosis of plants he then did for the Vertebrate
animals, in his celebrated vertebral theory of the skull.
Goethe was the first to show, independently of Oken, who
almost simultaneously arrived at the same thought, that the
skull of man and of all Vertebrate animals, in particular
mammals, is nothing more than a bony case, formed of
the same bones, — that is, vertebras, — out of which the spine
also is composed. The vertebrae of the skull are like those
of the spine, bony rings lying behind each other, but in the
skull are pecuHarly changed and specialized (differentiated).
Although this idea has been strongly modified by recent
discoveries, yet in Goethe's day it was one of the greatest
advances in comparative anatomy, and was not only one
of the first advances towards the understanding of the
structure of Vertebrate animals, but at the same time ex-
plained many individual phenomena. When two parts of a
body, such as the skull and spine, which appear at first
sight so different, were proved to be parts originally the
same, developed out of one and the same foundation, one of
the difficult problems of the philosophy of nature was
solved. Here again we meet the notion of a single type —
the conception of a single principle, which becomes in-

84 THE HISTORY OF CREATION.

finitely varied in the different species, and in the parts of
individual species.

But Goethe did not merely endeavour to search for such
far-reaching laws, he also occupied himself most actively
for a long time with numerous individual researches,
especially in comparative anatomy. Among these, none is
perhaps more interesting than the discovery of the onidjaiv-
hone in man. As this is, in several respects, of importance
to the theory of development, I shall briefly explain it
here. There exist in all mammals two little bones in the
upper jaw, which meet in the centre of the face, below the
nose, and which lie between the two halves of the real upper
jawbone. These two bones, which hold the four ujjper
cutting teeth, are recognized without difficulty in most
mammals ; in man, however, they were at that time un-
known, and celebrated comparative anatomists even laid
great stress upon this want of a mid jawbone, as they con-
sidered it to constitute the principal difference between men
and apes — the want of a mid jawbone was, curiously
enough, looked upon as the most human of all human
characteristics. But Goethe could not accept the notion
that man, who in all other corporeal respects was clearly
only a mammal of higher development, should lack this mid
jawbone.

By the general law of induction as to the mid jawbone
he arrived at the special deductive conclusion that it must
exist in man also, and Goethe did not rest until, after com-
paring a gi'eat number of human skulls, he really found
the mid jawbone. In some individuals it is preserved
throughout a whole lifetime, but usually at an early age
it coalesces with the neighbouring upper jawbone, and is

THEORY OF THE SKULL. 85

therefore only to be found as an independent bone in very
youthful skulls. In human embryos it can now be pointed
out at any moment. In man, therefore, the mid jawbone
actually exists, and to Goethe the honour is due of having
first firmly established this fact, so important in many
respects; and this he did while opposed by the celebrated
anatomist, Peter Camper, one of the most important pro-
fessional authorities. The way by which Goethe succeeded
in establishing this fact is especially interesting ; it is the
way by which we continually advance in biological science,
namely, by way of induction and deduction. Induction
is the inference of a general law from the observation of
numerous individual cases ; deduction, on the other hand,
is an inference from this general law applied to a single case
which has not yet been actually observed. From the col-
lected empirical knowledge of those days, the inductive
conclusion was arrived at that all mammals had mid jaw-
bones. Goethe drew from this the deductive conclusion,
that man, whose organization was in all other respects not
essentially different from mammals, must also possess this
mid jawbone ; and on close examination it was actually
found. The deductive conclusion was confirmed and verified
by experience.

Even these few remarks ma}^ serve to show the great
value which we must ascribe to Goethe's biological re-
searches. Unfortunately most of his labours devoted to
this subject are so hidden in his collected works, and his
most important observations and remarks so scattered in
numerous individual treatises — devoted to other subjects —
that it is difficult to find them out. It also sometimes
happens that an excellent, truly scientific remark is so

86 THE HISTORY OF CREATION.

mucli interwoven with a mass of useless philosophical
fancies, that the latter greatly detract from the former.

Nothing is perhaps more characteristic of the extraordi-
nary interest which Goethe took in the investigation of
organic nature than the lively way in which, even in his
last years, he followed the dispute which broke out in
France between Cuvier and Geofiroy de St. Hilaire. Goethe,
in a special treatise which was only finished a few days
before his death, in March, 1832, has given an interesting
description of this remarkable dispute and its general im-
portance, as well as an excellent sketch of the two great
opponents. This treatise bears the title " Principes de
Philosophic Zoologique par M. Geoifroy de Saint Hilaire " ;
it is Goethe's last work, and forms the conclusion of the
collected edition of his works. The dispute itself was, in
several respects, of the highest interest. It turned essentially
upon the justification of the theory of development. It
was carried on, moreover, in the bosom of the French
Academy, by both opponents, with a personal vehemence
almost unheard of in the dignified sessions of that learned
body ; this proved that both naturalists were fighting for
their most sacred and deepest convictions. The conflict
began on the 22nd of February, and was followed by
several others ; the fiercest took place on the 19th of
July, 1830. Geofiroy, as the chief of the French nature-
philosophers, represented the theory of natural development
and the monistic conception of nature. He maintained the
mutability of organic species, the common descent of the
individual species from common primary forms, and the
unity of their organization — or the unity of the plan of
structure, as it was then called.

GOETHE AND ST. HILAIRE. • 87

Cuvier was the most decided opponent of these views,
and according to what we have seen, it could not be
otherwise. He endeavoured to show that the nature-
philosophers had no right to rear such comprehensive con-
clusions on the basis of the empirical knowledge then
possessed, and that the unity of organization — or plan of
structure of organisms — as maintained by them, did not
exist. He represented the teleological (dualistic) concep-
tion of nature, and maintained that " the immutability of
species was a necessary condition for the existence of a
scientific history of nature." Cuvier had the great advan-
tage over his opponent, that he was able to bring towards
the proof of his assertions things obvious to the eye ; these,
however, were only individual facts taken out of their con-
nection with others. Geoffroy was not able to prove the
higher and general connection of individual phenomena
which he maintained, by equally tangible details. Hence
Cuvier, in the eyes of the majority, gained the victory, and
decided the defeat of the nature-philosophy and the
supremacy of the strictly empiric tendency for the next
thirty years.

Goethe of course supported Geoffroy's views. How deeply
interested he was, even in his 81st year, in this gi'eat contest
is proved by the following anecdote related by Soret : —

" Monday, Aug. 2nd, 1830. — The news of the outbreak of
the revolution of July arrived in Weimar to-day, and has
caused general excitement. In the course of the afternoon
I went to Goethe. * Well ? ' he exclaimed as I entered,
' what do you think of this great event ? The volcano has
burst forth, all is in flames, and there are no more negotia-
tions behind closed doors.' * A dreadful afl^air,' I answered ;

88 THE HISTOKY OF CREATION?.

* but what else could be expected under the circum-
stances, and with such a ministry, except that it would
end in the expulsion of the present royal family ? ' * We do
not seem to understand each other, my dear friend,^ replied
Goethe. ' I am not speaking of those people at all ; I am
interested in something very different, I mean the dispute
between Cuvier and Geoffi'oy de Saint Hilaire, which has
broken out in the Academy, and which is of such great im-
portance to science.' This remark of Goethe's came upon
me so unexpectedly, that I did not know what to say, and
my thoughts for some minutes seemed to have come to a
complete standstill. ' The affair is of the utmost import-
ance,' he continued, ' and you cannot form any idea of what
I felt on receiving the news of the meeting on the 19th.
In Geoffroy de Saint Hilaire we have now a mighty ally
for a long time to come. But I see also how great the
sympathy of the French scientific world must be in this
affair, for, in spite of the terrible political excitement, the
meeting on the 19th was attended by a full house. The
best of it is, however, that the synthetic treatment of
natm^e, introduced into France by Geoffroy, can now no
longer be stopped. This matter has now become public
through the discussions in the Academy, carried on in the
presence of a large audience; it can no longer be referred
to secret committees, or be settled or suppressed behind
closed doors.' "

In my book on " The General Morphology of Organisms "
I have placed as headings to the difierent books and chapters
a selection of the numerous interesting and important sen-
tences in which Goethe clearly expresses his view of
organic nature and its constant development. I will here

GOETHE ON ADAPTATION AND INHERITANCE. 89

quote a passage from the poem entitled, "The Metamor-
phosis of Animals " (1819).

" All members develop themselves according to eternal laws,
And the rarest form mysterionsly preserves the primitive type.
Form therefore determines the animal's way of life,
And in turn the way of life powerfully reacts upon all form.
Thus the orderly growth of form is seen to hold
Whilst yielding to change from externally acting causes." *

Here, clearly enough, the contrast between two different
organic constructive forms is intimated, which are opposed
to one another, and which by their inter-action determine
the form of the organism ; on the one hand, a common inner
original type, firmly maintaining itself, constitutes the
foundation of the most different forms ; on the other hand,
the externally active influence of surroundings and mode of
life, which influence the original type and transform it.
This Contrast is still more definitely pointed out in the
following passage : —

" An inner original community forms the foundation of all
organization ; the variety of forms, on the other hand, arises
from the necessary relations to the outer world, and we
may therefore justly assume an original difference of condi-
tions, together with an uninterruptedly progressive trans-
formation, in order to be able to comprehend the constancy
as well as the variations of the phenomena of form."

The *' original type " which constitutes the foundation of

* Alle Glieder bilden sich aus nach ew'gen Gesetzen,
TJnd die seltenste Form bewahrt im Geheimniss das Urbild.
Also bestimmt die Gestalt die Lebensweise des Thieres.
Und die Weise zu leben, sie wirkt auf alle Gestalten
Machtig zuriick. So zeiget sich fest die geordnete Bildung,
Welche zum Wechsel sich neigt durch ausserlich wirkende Wesen.

90 THE HISTORY OF CREATION.

every organic form " as the inner original community " is
the inner constructive force, which receives the original
direction of form-production — that is, the tendency to give
rise to a particular form — and is propagated by Inheritance.
The "uninterruptedly progressive transformation," on the
other hand, which " springs from the necessary relations to
the outer world," acting as an external formative force,
produces, by Adaptation to the surrounding conditions of
life, the "infinite variety of forms" (Gen. Morph. i. 154;
ii. 224). The internal formative tendency of Inheritance,
which retains the unity of the original type, is called by
Goethe in another passage the centripetal force of the organ-
ism, or its tendency to specification ; in contrast with this he
calls the external formative tendency of Adaptation, which
produces the variety of organic forms, the centrifugal force
of organisms, or their tendency to variation. The passage
in which he clearly indicates the " equilibrium " of these two
extremely important organic formative tendencies, runs as
follows : " The idea of metamorphosis resembles the vis
centrifuga, and would lose itself in the infinite, if a counter-
poise were not added to it : I mean the tendency to specifi-
cation, the strong power to preserve what once has come
into being, a vis centripeta, which in its deepest foundation
cannot be affected by anything external."

Metamorphosis, according to Goethe, consists not merely,
as the word is now generally understood, in the changes of
form which the organic individual experiences during its
individual development, but, in a wider sense, in the
transformation of organic forms in general. His idea of
metamorphosis is almost synonymous with the theory of
development. This is clear, among other things, from the

Goethe's speculations. 91

following passage : — " The triumph of physiological meta-
morphosis manifests itself where the whole separates and
transforms itself into families, the families into genera, the
genera into species, and then again into other varieties
down to the individual. This operation of nature goes on
ad infinitum ; she cannot rest inactive, but neither can she
keep and preserve all that she has produced. From seeds
there are always developed varying plants, exhibiting the
relations of their parts to one another in an altered manner."

Goethe had, in truth, discovered two great mechanical
forces of nature, which are the active causes of organic
formations, his two organic formative tendencies — on the
one hand the conservative, centripetal, and internal forma-
tive tendency of Inheritance or specification ; and on the
other hand the progressive, centrifugal, and external form-
ative tendency of Adaptation, or metamorphosis. This
profound biological intuition could not but lead him natur-
ally to the fundamental idea of the Doctrine of Filiation, that
is, to the conception that the organic species resembling one
another in form are actually related by blood, and that they
are descended from a common original type. In regard to
the most important of all animal groups, namely that ot
Vertebrate animals, Goethe expresses this doctrine in the
following passage (1796 ) : — " Thus much then we have
gained, that we may assert without hesitation that all the
more perfect organic natures, such as fishes, amphibious
animals, birds, mammals, and man at the head of the last,
were all formed upon one original type, which only varies
more or less in parts which are none the less permanent, and
still daily changes and modifies its form by propagation."

This sentence is of interest in more than one way. The

92 THE HISTORY OF CREATION.

theory that all " the more perfect organic natures," that is
all Vertebrate animals, are descended from one common
prototype, that they have arisen from it by propagation
(Inheritance) and transformation (Adaptation), may be
distinctly inferred. But it is especially interesting to
observe that Goethe admits no exceptional position for man,
but rather expressly includes him in the tribe of the other
Vertebrate animals. The most important special inference
of the Doctrine of Filiation, that man is descended from
other Vertebrate animals, may here be recognized in the
germ.^

This exceedingly important ftmdamental idea is expressed
by Goethe still more clearly in another passage (1807), in
the following words : — " If we consider plants and animals in
their most imperfect condition, they can scarcely be distin-
guished. But this much we can say, that the creatures
which by degrees emerge as plants and animals out of a
common phase, where they are barely distinguishable, anive
at perfection in two opposite directions ; so that the plant in
the end reaches its highest glory in the tree, which is
immovable and stiff, the animal in man, who possesses
the greatest elasticity and freedom." This remarkable
passage not only indicates most explicitly the genealogical
relationship between the vegetable and animal kingdoms,
but contains the germ of the monophyletic hypothesis of
descent, the importance of which I shall have to explain
hereafter. (Compare Chapter XVI. and the Pedigree,
p. 898.)

At the time when Goethe in this way sketched the
fundamental features of the Theory of Descent, another
German philosopher, Gottfried Reinhold Treviranus, of

TEEVIRANUS, THE FIRST NATUEE-PHILOSOPHEE. 93

Bremen (born 1776, died 1837), was zealously engaged at
the same work. As Wilhelm Focke has recently shown,
Treviranus, even in the earliest of his greater works, " The
Biology or Philosophy of Animate Nature," which appeared
at the beginning of the present century, had already
developed monistic views of the unity of nature, and of the
genealogical connection of the species of organisms, which
entirely correspond with our present view of the matter. In
the first three volumes of the Biology, which appeared succes-
sively in 1802, 1803, and 1805 (therefore several years before
Oken's and Lamarck's principal works), we find numerous
passages which are of interest in this respect. I shall here
quote only a few of the most important.

In speaking of the principal question of our theory, the
question of the origin of organic species, Treviranus makes
the following remarks : — " Every form of life can be
produced by physical forces in one of two ways : either by
coming into being out of formless matter, or by modification
of an already existing form by a continued process of
shaping. In the latter case the cause of this modification
may lie either in the influence of a dissimilar male genera-
tive matter upon the female germ, or in the influence of
other powers which operate only after procreation. In every
living being there exists the capability of an endless variety
of form-assumption ; each possesses the power to adapt its
organization to the changes of the outer world, and it is this
power put into action by the change of the universe that
has raised the simple zoophytes of the primitive world to
continually higher stages of organization, and has introduced
a countless variety of species into animate nature."

By zoophytes, Treviranus here means organisms of the

94 THE HISTORY OF CREATION.

lowest order and of the simplest character, namely, those
neutral primitive beings which stand midway between
animals and plants, and on the whole correspond with our
protista. " These zoophytes," he remarks in another pass-
age, "are the original forms out of which all the organisms
of the higher classes have arisen by gradual development.
We are further of opinion that every species, as well as
every individual, has certain periods of growth, of bloom,
and of decay, but that the decay of a species is degeneration,
not dissolution, as in the case of the individual. From this it
appears to us to follow that it was not the great catastrophes
of the earth" (as is generally supposed) which destroyed the
animals of the primitive world, but that many survived
them, and it is more probable that they have disappeared
from existing nature, because the species to which they
belonged have completed the circle of their existence, and
have become changed into other kinds."

When Treviranus, in this and other passages, points to
degeneration as the most important cause of the transforma-
tion of the animal and vegetable species, he does not under-
stand by it what is now commonly called degeneration.
With him "degeneration" is exactly what we now call
Adaptation or modification, by the action of external
formative forces. That Treviranus explained this trans-
transformation of organic species by Adaptation, and its
preservation by Inheritance, and thus the whole variety of
organic forms by the inter-action of Adaptation and In-
heritance, is clear also from several other passages. How
profoundly he grasped the mutual dependence of all living
creatures on one another, and in general the universal
connection between cause and effect — that is, the monistic

TEEVIRANUS ON SOLIDARITY. 95

causal connection between all members and parts of the
universe — is further shown, among others, by the following
remarks in his Biology : — " The living individual is depen-
dent upon the species, the species upon the fauna, the fauna
upon the whole of animate nature, and the latter upon the
organism of the earth. The individual possesses indeed a
peculiar life, and so far forms its own world. But just
because its life is limited it constitutes at the same time an
organ in the general organism. Every living body exists in
consequence of the universe, but the universe, on the other
hand, exists in consequence of it."

It is self-evident that so profound and clear a thinker as
Treviranus, in accordance with this grand mechanical con-
ception of the universe, could not admit for man a privileged
and exceptional position in nature, but assumed his gradual
development from lower animal forms. And it is equally
self-evident, on the other hand, that he did not admit a
chasm between organic and inorganic nature, but main-
tained the absolute unity of the organization of the whole
universe. This is specially attested by the following
sentence : — " Every inquiry into the influence of the whole
of nature on the living world must start from the principle,
that all living forms are products of physical influences,
which are acting even now, and are changed only in degree,
or in their direction." Hereby, as Treviranus himself says,
" The fundamental problem of biology is solved," and we
add, solved in a purely mechanical or monistic sense.

Neither Treviranus nor Goethe is commonly considered
the most eminent of the German nature-philosophers, but
Lorenz Oken, who, in establishing the vertebral theory of the
skull, came forward as a rival to Goethe, and did not

96 THE HISTORY OF CREATION.

entertain a very kindly feeling towards him. Altliough they
lived for some time in the same neighbourhood, yet the
natures of these two men were so very different, that they
could not well be drawn towards each other. Oken's " Manual
of the Philosophy of Nature," which may be designated as the
most important production of the nature-philosophy school
then existing in Germany, appeared in 1809, the same year
in which Lamarck's fundamental work, the " Philosophic
Zoologique," was published. As early as 1802, Oken had
published an " Outline of the Philosophy of Nature." As we
have already intimated, in Oken's as in Goethe's works, a
number of valuable and profound thoughts are hidden
among a mass of erroneous, very eccentric, and fantastic con-
ceptions. Some of these ideas have only quite recently and
gradually become recognized in science, many years after
they were first expressed. I shall here quote only two
thoughts, which are almost prophetic, and which at the
same time stand in the closest relation to the theory of
development.

One of the most important of Oken's theories, which was
formerly very much decried, and was most strongly com-
batted, especially by the so-called " exact experimentalists,"
is the idea that the phenomena of life in all organisms pro-
ceed from a common chemical substance, so to say, from a
general simple vitcd-suhstance, which he designated by the
name Ursclileim, or original slime. By it he meant, as the
name indicates, a mucilaginous substance, an albuminous
combination, which exists in a semi-fluid condition of aggre-
gation, and possesses the power, by adaptation to different
conditions of existence in the outer world and by inter-
action with its material, of producing the most various forms

OKENS THEORIES. 97

I^ow, we need only change the expression ''original slime"
(Urschleim) into Protojplasmi, or cell-suhstance, in order to
arrive at one of the grandest results which we owe to
microscopic investigations during the last ten years, more
especially to those of Max Schultze. By these investigations
it has been shown that in all living^ bodies, without ex-
ception, there exists a certain quantity of mucilaginous albu-
minous matter, in a semi-fluid condition; and that this
nitrogen-holding carbon-compound is exclusively the ori-
ginal seat and agent of all the phenomena of life, and of
all production of organic forms. All other substances which
appear in the organism, besides these, are either formed by
this active matter of life, or have been introduced from with-
out. The organic egg, the original cell out of which every
animal and plant is first developed, consists essentially only
of one round little lump of such albuminous matter. Even
the yolk of an egg is nothing but albumen, mixed with
granules of fat. Oken was therefore right when, more
divining than knowing, he made the assertion — "Every
organic thing has arisen out of slime, and is nothing but
slime in different forms. This primitive slime originated
in the sea, from inorganic matter in the course of planetary-
evolution."

Another equally grand idea of the same philosopher is
closely connected with his theory of primitive slime, which
coincides with the extremely important Protoplasm theoru
Eor Oken, as early as 1809, asserted that the primitive
slime produced in the sea by spontaneous generation, at
once assumed the form of microscopically small bladders,
which he called " Mile'' or " Infusoria!' " Organic nature
has for its basis an infinity of such vesicles." These little

98 THE HISTOHY OF CEEATION.

bladders arise from original semi-fluid globules of the primi-
tive slime, by the fact of their periphery becoming con-
densed. The simplest organism, as well as every animal and
every plant of higher kind, is nothing else than " an accu-
mulation (synthesis) of such infusorial bladders, which
by various combinations assume various forms, and thus
develop into higher organisms." Here again we need only
translate the expression little bladder, or infusorium, by the
word cell, and we arrive at the Cell theory, one of the
grandest biological theories of our century. Schleiden and
Schwann, about thirty years ago, were the first to furnish
experiential proof that all organisms are either simple cells,
or accumulations (syntheses) of such cells, and the more recent
protoplasm theory has shown that protoplasm (the original
slime) is the most essential (and sometimes the only) con-
stituent part of the genuine cell. The properties which Oken
ascribes to his Infusoria are exactly the properties of cells,
the properties of elementary beings, by whose accumulation,
combination, and varying development, the higher organisms
are formed.

These two extremely fruitful thoughts of Oken, on account
of the absurd form in which he expressed them, were at
first little heeded, or entirely misunderstood, and it was re-
served for a much later era to establish them by actual
observation. The supposition that the individual species of
plants and animals originated from common prototypes by
a slow and gTadual development of the higher organisms out
of lower ones, was of course most closely connected with
these ideas. Man's descent from lower organisms was like-
wise asserted by Oken — " Man has been developed, not
created." Although many arbitrary perversities and ex-

THE NATUH-PHILOSOPHIE. 99

travagant fancies may be found in Oken's philosophy of
nature, they must not prevent us paying our just admira-
tion to these grand ideas, which were so far in advance of
their age. This much is clearly evident from the statements
of Goethe and Oken which we have quoted, and from the
views of Lamarck and Geoffroy which have to be discussed
next, that during the first decade of our century no
doctrine approached so nearly to the natural Theory of
Descent, newly established by Darwin, as the much decried
" Natxir-philosophie."

lOO - THE HISTORY OF CKEATION.

CHAPTER V.

THEORY OF DEYELOPMENT ACCORDING TO KANT

AND LAMARCK.

Kant's Dnalistic Biology. — His Conception of tlie Origin of Inorganic
Nature by Mechanical Causes, of Organic Nature by Causes acting for a
Definite Purpose. — Contradiction of this Conception with his leaning
towards the Theory of Descent. — Kant's Genealogical Theory of
Development. — Its Limitation by his Teleology. — Comparison of
Genealogical Biology with Comparative Philology. — Views in favour of
the Theory of Descent entertained by Leopold Buch, Bar, Schleiden,
Unger, Schaafhausen, Victor Cams, Biichncr. — French Nature,
philosophy. — Lamarck's Philosophic Zoologique. — Lamarck's Monistic
(mechanical) System of Nature. — His Views of the Inter-action of the
Two Organic Formative Tendencies of Inheritance and Adaptation. —
Lamarck's Conception of Man's Development from Ape-like Mammals. —
Geoffroy St. Hilaire's, Naudin's, and Lecoq's Defence of the Theory of
Descent. — English Nature-philosophy. — Views in favour of the Theory
of Descent, entertained by Erasmus Darwin, W. Herbert, Grant, Freke,
Herbert Spencer, Hooker, Huxley. — The Double Merit of Charles
Dar^vin.

The teleological view of nature, wliich explains the plie-
nomena of the organic world by the action of a personal
Creator acting for a definite purpose, necessarily leads, when
carried to its extreme consequences, either to utterly unten-
able contradictions, or to a twofold (dualistic) conception
of nature, which most directly contradicts the unity and
simplicity of the supreme laws which are everywhere
perceptible. The philosophers who embrace teleology must

K ant's biological theories. to I

necessarily assume two fundamentally different natures :
an inorganic nature, wliich must be explained by causes
acting mechanically (causae efficientes), and an organic
nature, which must be explained by causes acting for a
definite purpose (causae finales). (Compare p. 34.)

This dualism meets us in a striking manner when con-
sidering the conceptions of nature formed by Kant, one of
the greatest German philosophers, and his ideas of the com-
ing into being of organisms. A closer examination of these
ideas is forced upon us here, because in Kant we honour one
of the few philosophers who combine a solid scientific cul-
ture with an extraordinary clearness and profundity of
speculation. The Konigsberg philosopher gained the highest
celebrity, not only among speculative philosophers as the
founder of critical philosophy, but acquired a brilliant name
also among naturalists by his mechanical cosmogeny. Even
in the year 1755, in his " General History of Nature, and
Theory of the Heavens," ^ he made the bold attempt " to
discuss the constitution and the mechanical origin of the
whole universe, according to Newton's principles," and to
explain them mechanically by the natural course of develop-
ment, to the exclusion of all miracles. This cosmogeny of
Kant, or " cosmological gas theory," which we shall briefly
discuss in a future chapter, was at a later day fully estab-
lished by the French mathematician Laplace and the Eng-
lish astronomer Herschel, and enjoys at the present day
almost universal recognition. On account of this import-
ant work alone, in which exact knowledge is co^upled
with most profound speculation, Kant deserves the honour-
able name of a natural philosopher in the best and purest

sense of the word.
6

I02 THE HISTORY OF CREATION.

If we read Kant's Criticism of the Teleological Faculty
of Judgment, his most important biological work, we
perceive that in contemplating organic nature he always
maintains what is essentially the teleological or dualistic
point of view ; whilst for inorganic nature he, uncondition-
ally and without reserve, assumes the mechanical or monis-
tic method of explanation. He affirms that in the domain
of inorganic nature all the phenomena can be explained by
mechanical causes, by the moving forces of matter itself, but
not so in the domain of organic nature. In the whole of
Anorganology (in Geology and Mineralogy, in Meteorology
and Astronomy, in the physics and chemistry of inorganic
natural bodies), all phenomena are said to be explicable
merely by 'mechanism (causa efficiens), without the interven-
tion of a final purpose. In the whole domain of Biology, on
the other hand — in Botany, Zoology, and Anthropology — me-
chanism is not considered sufficient to explain to us all their
phenomena ; but we are supposed to be able to comprehend
them only by an assumption of 2, final cause acting for a defi-
nite purpose (causa finahs). In several passages Kant em-
phatically remarks that, from a strictly scientific point of
view, all phenomena, without exception, require a mechani-
cal interpretation, and that mechanism alone can offer a true
exi^lanation. But at the same time he thinks, that in regard
to living natural bodies, animals and plants, our human
power of comprehension is limited, and not sufficient for
arriving at the real cause of organic processes, especially at
the origin of organic forms. The right of human reason to
explain all phenomena mechanically is unlimited, he says,
but its poiuer is limited by the fact that organic nature can
be conceived only from a teleological point of view.

KANTS BIOLOGICAL THEORIES. IO3

Some passages are, however, very remarkable, in which
Kant in a surprising manner deviates from this mode of
viewing things, and expresses, more or less distinctly, the
fundamental idea of the Theory of Descent. He even as-
serts the necessity of a genealogical conception of the series
of organisms, if we at all wish to understand it scien-
tifically. The most important and remarkable of these pas-
sages occurs in his " Methodical System of the Teleological
Faculty of Judgment " (§ 79), which appeared in 1790 in the
" Criticism of the Faculty of Judgment." Considering the
extraordinary interest which this passage possesses, both for
forming a correct estimate of Kant's philosophy, as well as
for the Theory of Descent, I shall here insert it verhatim.

" It is desirable to examine the great domain of organized
nature by means of a methodical comparative anatomy, in
order to discover whether we may not find in it something
resembling a system, and that too in connection with the
mode of generation, so that we may no longer be compelled
to stop short with a mere consideration of forms as they are
— which gives us no insight into their generation — and need
no longer give up in despair all hope of gaining a full insight
into this department of nature. The agreement of so many
kinds of animals in a certain common plan of structure, which
seems to be visible not only in their skeletons, but also in the
arrangement of the remaining parts — so that a wonderfully
simple typical form, by the shortening and lengthening of
some parts, and by the suppression and development of
others, might be able to produce an immense variety of
species — gives us a ray of hope, though feeble, that here
perhaps some result may be obtained, by the application of
the principle of the mechanism of nature, without which.

104 THE HISTORY OF CREATION.

in fact, no science can exist. This analogy of forms (in so
far as they seem to have been produced in accordance with
a common prototype, notwithstanding their great variety)
strengthens the supposition that they have an actual blood-
relationship, due to origination from a common parent; a
supposition which is arrived at by observation of the
graduated approximation of one class of animals to another,
beginning with the one in which the principle of purposive-
ness seems to be most conspicuous, that is man, and extend-
ing down to the polyps, and from these even down to mosses
and lichens, and arriving finally at raw matter, the lowest
stage of nature observable by us. From this matter and
its forces the whole apparatus of Nature seems to have
descended according to mechanical laws (such as those
which she follows in the production of crystals) ; yet this
apparatus, as seen in organic beings, is so incomprehensible
to us, that we feel ourselves compelled to conceive for it a
different principle. But it would seem that the archaeologist
of Nature is at liberty to regard the great Family of
creatures (for as a Family we must conceive it, if the above-
mentioned continuous and connected relationship has a real
foundation) as having sprung from the immediate results of
her earliest revolutions, judging from all the laws of their
mechanism known to or conjectured by him."

If we take this remarkable passage out of Kant's
" Criticism of the Teleological Faculty of Judgment," and
consider it by itself, we cannot but be astonished to find
how profoundly and clearly the great thinker, even in 1790,
had recognized the inevitable necessity of the Doctrine
of Descent, and designated it as the only possible way of
explaining organic nature by mechanical laws — that is, by

KANT AS A TELEOLOGIST. I05

true scientific reasoning. On account of tliis one passage
taken by itself, we might place Kant beside Goethe and
Lamarck, as one of the first founders of the Doctrine of
Descent ; and considering the high authority which Kant's
Critical Philosophy most justly enjoys, this circumstance
might perhaps induce many a philosopher to decide in
favour of the theory. But as soon as we consider this
passage in connection with the other train of thoughts in
the " Criticism of the Faculty of Judgment," and balance
it against other directly contradictory passages, we see
clearly that Kant, in these and some similar (but weaker)
sentences, went beyond himself, and abandoned the teleo-
logical point of view which he usually adopts in Biology.

Directly after the admirable passage which I have just
quoted, there follows a remark which completely takes off
its edge. After having quite correctly maintained the
origin of organic forms out of raw matter by mechanical
laws (in the manner of crystallization), as well as a gTadual
development of the different species by descent from one
common original parent, Kant adds, " But he (the archseolo-
gist of nature, that is the palseontologist) must for this end
ascribe to the common mother an organization ordained
purposely with a view to the needs of all her offspring,
otherwise the possibility of suitability of form in the pro-
ducts of the animal and vegetable kingdoms (i.e. teleological
adaptation) cannot be conceived at all." This addition
clearly contradicts the most important fundamental thought
of the preceding passage, viz. that a purely mechanical ex-
planation of organic nature becomes possible through the
Theory of Descent. And that the teleological conception
of organic nature predominated with Kant, is shown by

I06 THE HISTOEY OF CREATION.

the heading of the remarkable § 79, which contains the two
contradictory passages cited : " Of the Necessary Suhordinar-
tion of the Mechanical to the Teleological FrineiiDle, in the
explanation of a thing as a lourpose or object of Nature."

He expresses himself most decidedly against the mechanical
explanation of organic nature in the following passage
(§ 74) : "It is quite certain that we cannot become sufficiently
acquainted with organized creatures and their hidden
potentialities by aid of purely mechanical natural principles,
much less can we explain them ; and this is so certain, that
we may boldly assert that it is absurd for man even to con-
ceive such an idea, or to hope that a Newton may one day
arise able to make the production of a blade of grass com-
prehensible, according to natural laws ordained by no inten-
tion; such an insight we must absolutely deny to man."
Now, however, this impossible Newton has really appeared
seventy years later in Darwin, whose Theory of Selection
has actually solved the problem, the solution of which
Kant had considered absolutely inconceivable !

In connection with Kant and the German philosoj^hers
whose theories of development have already occupied us in
the preceding chapter, it seems justifiable to consider briefly
some other German naturalists and philosophers, who, in the
course of our century, have more or less distinctly resisted
the prevailing teleological views of creation, and vindicated
the mechanical conception of things which is the basis of
the Doctrine of Filiation. Sometimes general philosophical
considerations, sometimes special emj^irical observations,
were the motives which led these thinking men to form the
idea that the various individiial species of organisms must
have originated from common primary forms. Among them

LEOPOLD BUCH. IO7

I must first mention tlie great German geologist, Leopold
Buch. Important observations as to the geographical dis-
tribution of plants led him to the following remarkable
assertion in his excellent "Physical Description of the
Canary Islands " : —

"The individuals of genera, on continents, spread and
widely diffuse themselves, and by the difference of localities,
nourishment, and soil, form varieties ; and being in conse-
quence of their isolation never crossed by other varieties,
and so brought back to the main type, they in the end
become a permanent and a distinct species. Then, perhaps,
in other ways, they once more become associated with other
descendants of the original form — which have likewise
become new varieties — and both now appear as very distinct
species, no longer mingling with one another. Not so on
islands. Being commonly confined in narrow valleys or
within the limit of small zones, individuals can reach one
another and destroy every commencing production of a per-
manent variety. Much in the same way the peculiarities or
faults in language, originating with the head of some family,
become, through the extension of the family, indigenous
throughout a whole district. If the district is separated and
isolated, and if the language is not brought back to its
former purity by constant connection with that spoken in
neighbouring districts, a dialect will be the result. If natural
obstacles, forests, constitution, form of government, unite
the inhabitants of the separate district still more closely,
and separate them still more completely from their neigh-
bours, the dialect is fixed, and becomes a completely
distinct language." (Uebersicht der Flora auf den Canarien,

a 133.)

i

1 08 THE HISTORY OF CREATION.

We perceive that Bueli is here led to the fundamental
idea of the Theory of Descent by the phenomena of the
geography of plants, a department of biological knowledge
which in fact furnishes a mass of proofs in favour of it.
Darwin has minutely discussed these proofs in two separate
chapters of his book (the 11th and 12th). Buch's remark is
further of interest, because it leads us to the exceedingly
instructive comparison of the different branches of language
with the species of organisms, a comparison which is of the
greatest use to Comparative Philology, as well as to Compara-
tive Botany and Zoology. Just as, for example, the different
dialects, provincialisms, branches, and off-shoots of the
German, Slavonic, Greco-Latin, and Irano-Indian parent lan-
guage, are derived from a single common Indo- Germanic
parent tongue, and just as their differences are explained by
Adaptation, and their common fundamental characters ex-
plained hy Inheritance, so in like manner the different species,
genera, families, orders, and classes of Vertebrate animals
are derived from a single common vertebrate form of animal.
Here also Adaptation is the cause of differences, Inheritance
the cause of community of character. This interesting
parallelism in the divergent development of the forms of
speech and the forms of organisms has been discussed in
the clearest manner by one of our first comparative philolo-
gists, the talented Augustus Schleicher, whose premature
death, four years ago, remains an irreparable loss, not only
to our University of Jena, but to the whole of monistic
science.^

Among other eminent German naturalists who have ex-
pressed their belief in the Theory of Descent more or less
distinctly, arriving at their conclusion in very various ways.

BAR, SCHLEIDEN, UNGER. IO9

I must next mention Carl Ernst Bar, the great reformer of
animal embryology. In a lecture delivered in 1834, entitled
" The Most General Laws of Nature in All Development,"
he shows, in the clearest way, that only in a very childish
view of nature could organic species be regarded as perma-
nent and unchangeable types, and that really they can be
only passing series of generations, which have developed by
transformation from a common original form. The same
conception again received firm support from Baer, in 1859,
through a consideration of the of laws the geographical
distribution of organisms.

J. M. Schleiden, who founded, thirty years ago, in Jena, a
new epoch in Botany by his strictly empirico-philosophical
and truly scientific method, illustrated the philosophical
significance of the conception of organic species in his inci-
sive " Outlines of Scientific Botany," "^ and showed that it
had only a subjective origin in the general law of sjpecifica-
tion. The difierent species of plants are only the specified
productions of the formative tendencies of plants, which arise
from the various combinations of the fundamental forces of
organic matter.

The eminent botanist, F. Unger, of Vienna, was led by
his profound and comprehensive investigations on extinct
vegetable species, to a palseontological history of the de-
velopment of the vegetable kingdom, which distinctly asserts
the principle of the Theory of Descent. In his " Attempt at
a History of the World of Plants " (1852), he maintains the
derivation of all different species of plants from a few
primary forms, and perhaps from a single original plant, a
simple vegetable cell. He shows that this view is founded
on the genetic connection of all vegetable forms, and is

no THE HISTORY OF CREATION.

necessary, not merely upon philosophical grounds, but upon
those of experience and observation.^

Victor Cams, of Leipzig, in the Introduction to his
excellent "System of Animal Morphology,"^ published in
1853, in which he endeavours to establish in a philosophical
manner the universal constructive laws of the animal body
through comparative anatomy and the history of develop-
ment, makes the following remark : — " The organisms buried
in the most ancient geological strata must be looked upon
as the ancestors from whom the rich diversity of forms of
the present creation have originated by continued genera-
tion, and by accommodation to progressive and very different
conditions of life."

In the same year (1858) Schaaffhausen, the anthropologist
of Bonn, in an Essay " On the Permanence and Transforma-
tion of Species," declared himself decidedly in favour of the
Theory of Descent. According to him, the living species of
animals and plants are the transformed descendants of ex-
tinct species, from which they have arisen by gradual modi-
fication. The divergence or separation of the most nearly
allied species takes place by the destruction of the connect-
ing intermediate stages. Schaaffhausen also maintained,
with distinctness, the origin of the human race from ani-
mals, and its gradual development from ape-like animals, the
most important deduction from the Doctrine of Filiation.

Lastly, we have still to mention among the German Nature-
philosophers the name of Louis Bilchner, who, in his cele-
brated work, "Force and Matter" (1855), also independently
developed the principles of the Theory of Descent, taking
his stand mainly on the ground of the undeniable evidences
of fact which are furnished by the palajontological and in-

Lamarck's philosophy. hi

dividual development of organisms, as well as by their com-
parative anatomy and by the parallelism of these series of
development. Bllchner showed very clearly that, even from
such data alone, the derivation of the different organic
species from common primary forms followed as a necessary
conclusion, and that the origin of these original primary
forms could only be conceived of as the result of a sponta-
neous generation.

We now tiu-n from the German to the French Nature-
philosophers, who have likewise held the Theory of Descent,
since the beginning of the present century. At their head
stands Jean Lamarck, who occupies the first place next
to Darwin and Goethe in the history of the Doctrine of
Filiation. To him will always belong the immortal glory of
having for the first time worked out the Theory of Descent,
as an independent scientific theory of the fii'st order, and as
the philosophical foundation of the whole science of Biology.
Although Lamarck was born as early as 1744?, he did not
begin the publication of his theory until the commence-
ment of the present century, in 1801, and established it more
fully only in 1809, in his classic " Philosophic Zoologique." ^
This admirable work is the first connected exposition of the
Theory of Descent carried out strictly into all its conse-
quences. By its purely mechanical method of viewing
organic nature, and the strictly philosophical proofs brought
forward in it, Lamarck's work is raised far above the pre-
vailing dualistic views of his time ; and with the exception
of Darwin's work, which appeared just half a century later,
we know of none which we could in this respect place
by the side of the " Philosophic Zoologique." How far it was
in advance of its time is perhaps best seen ftom the cir-

112 THE HISTORY OF CREATION.

cumstance that it was not understood by most men, and for
fifty years was not spoken of at all. Cuvier, Lamarck's
greatest opponent, in his " Report on the Progress of Natural
Sciences/' in which the most unimportant anatomical inves-
tigations are enumerated, does not devote a single word to
this work, which forins an epoch in science. Goethe, also, who
took such a lively interest in the French nature-philosophy
and in " the thoughts of kinelred minds beyond the Rhine,'*
nowhere mentions Lamarck, and does not seem to have
known the " Philosophic Zoologique " at all. The great repu-
tation which Lamarck gained as a naturalist he does not owe
to his highly important general work, but to numerous special
treatises on the lower animals, particularly on Molluscs,
as well as to an excellent " Natural History of Invertebrate
Animals," which appeared, in seven volumes, between the
years 1815-1822. The first volume of this celebrated work
contains in the general introduction a detailed exposition of
his theory of filiation. I can, perhaps, give no better
idea of the extraordinary importance of the " Philosophie
Zoologique" than by quoting vevhatmi some of the most
important passages therefrom : —

" The systematic divisions of classes, orders, families,
genera, and species, as well as their designations, are the
arbitrary and artificial productions of man. The kinds or
species of organisms are of unequal age, developed one after
the other, and show only a relative and temporary persist-
ence ; species arise out of varieties. The differences in the
conditions of life have a modifying influence on the organ-
ization, the general form, and the parts of animals, and so
has the use or disuse of organs. In the first beginning only
the very simplest and lowest animals and plants came into

LAMARCK S PHILOSOPHY. 1 13

existence ; those of a more complex organization only at a
later period. The course of the earth's development, and
that of its organic inhabitants, was continuous, not inter-
rupted by violent revolutions. Life is purely a physical
phenomenon. All the phenomena of life depend on
mechanical, physical, and chemical causes, which are in-
herent in the nature of matter itself The simplest animals
and the simplest plants, which stand at the lowest point in
the scale of organization, have originated and still originate
by spontaneous generation. All animate natural bodies or
organisms are subject to the same laws as inanimate natural
bodies or anorgana. The ideas and actions of the under-
standing are the motional phenomena of the central nervous
system. The will is in truth never free. Reason is only a
higher degree of development and combination of judg-
ments."

These are indeed astonishingly bold, grand, and far-reach-
ing views, and were expressed by Lamarck sixty years ago ;
in fact, at a time when their establishment, by a mass of
facts, was not nearly as possible as it is in our day. Indeed
Lamarck's work is really a complete and strictly monistic
(mechanical) system of nature, and all the important general
principles of monistic Biology are already enunciated by
him : the unity of the active causes in organic and inorganic
nature ; the ultimate explanation of these causes in the
chemical and physical properties of matter itself; the
absence of a special vital power, or of an organic final cause ;
the derivation of all organisms from some few, most simple
original forms, which have come into existence by spon-
taneous generation out of inorganic matter ; the coherent
course of the whole earth's history ; the absence of

114 'THE HISTORY OF CREATION.

violent cataclysmic revolutions ; and in general the incon-
ceivableness of any miracle, of any supernatural interference,
in the natural course of the development of matter.

The fact that Lamarck's wonderful intellectual feat met
with scarcely any recognition, arises partly from the im-
mense length of the gigantic stride with which he had
advanced beyond the next fifty years, partly from its
defective empirical foundation, and from the somewhat one-
sided character of some of his arguments. Lamarck quite
correctly recognizes Adaptation as the first mechanical
cause which effects the continual transformation of organic
forms, while he traces with equal justice the similarity
in form of difierent species, genera, families, etc., to their
blood-relationship, and thus explains it by Inheritance.
Adaptation, according to him, consists in this, that the per-
petual, slow change of the outer world causes a corre-
sponding change in the actions of organisms, and thereby
also causes a further change in their forms. He lays the
greatest stress upon the efiect of habit upon the use and
disuse of organs. This is certainly of great importance
in tlie transformation of organic forms, as we shall see
later. However, the way in which Lamarck wished to
explain exclusively, or at any rate mainly, the change of
forms, is after all in most cases not possible. He says, for
example, that the long neck of the girafie has arisen from its
constantly stretching out its neck at high trees, and from
the endeavour to pick the leaves off their branches ; as
giraffes generally inhabit dry districts, where only the
foliage of trees afford them nourishment, they were forced
to this action. In like manner the longr toncjues of wood-
peckers, humming-birds, and ant-eaters, are said by him to

LAMAECK ON ADAPTATION. II5

have arisen from the habit of fetching their food out of
narrow, small, and deep crevices or channels. The webs
between the toes of the webbed feet in frogs and other
aquatic animals have arisen solely from the constant endea-
vour to swim, from striking their feet against the water,
and from the very movements of swimming. Inheritance
fixed these habits on the descendants, and finally, by further
elaboration, the organs were entirely transformed. However
correct, as a whole, this fundamental thought may be, yet
Lamarck lays the ^Lress too exclusively on habit (use and
non-use of organs), certainly one of the most important, but
not the only cause of the change of forms. Still this cannot
prevent our acknowledging that Lamarck quite correctly
appreciated the mutual co-operation of the two organic
formative tendencies of Adaptation and Inheritance. What
he failed to grasp is the exceedingly important principle of
" Natural Selection in the Struggle for Existence," with
which Darwin, fifty years later, made us acquainted.

It still remains to be mentioned as a special merit of
Lamarck, that he endeavoured to prove the development of
the human race from other primitive, ape-like mammals
Here again it was, above all, to habit that he ascribed the
transforming, the eimobling influence. He assumed that the
lowest, original men had originated out of men-like apes, by
the latter accustoming themselves to walk upright. The
raising of the body, the constant efibrt to keep upright, in
the first place led to a transformation of the limbs, to a
stronger difierentiation or separation of the fore and hinder
extremities, which is justly considered one of the most
essential distinctions between man and the ape. Behind,
the calf of the leg and the flat soles of the feet were

Il6 THE HISTORY OF CHEATION.

developed ; in front, the arms and hands, for the purpose of
seizing objects. The upright walk v.^as then followed by a
freer view over the suiTounding objects, and led consequently
to an important progress in mental development. Human
apes thereby soon gained a great advantage over the other
apes, and further, over surrounding organisms in general.
In order to maintain the supremacy over them, they
formed themselves into companies, and there arose, as in the
case of all animals living in company, the desire of com-
municating to one another their desires and thoughts. Thus
arose the necessity of language, which, consisting at first of
rough and disjointed sounds, soon became more connected,
developed, and articulate. The development of articulate
speech now in turn became the strongest lever for a further
progressive development of the organism, and above all, of
the brain, and so ape-like men became gradually and slowly
transformed into real men. In this way the actual descent of
the lowest and rudest primitive men from the most highly
developed apes was distinctly maintained by Lamarck, and
supported by a series of the most important proofs.

The honour of being the chief French nature-philosopher is
not usually assigned to Lamarck, but to Etienne Geofiroy St.
Hilaire (the elder), born in 1771, the same in whom Goethe
was especially interested, and with whom we have already
become acquainted as Cuvier's most prominent opponent.
He developed his ideas about the transformation of organic
species as far back as the end of the last century, but
published them only in the year 1828, and then in the fol-
lowing years, especially in 1880, defended them bravely
against Cuvier. Geoffroy St. Hilaire in all essentials
adopted Lamarck's Theory of Descent, yet he believed that

GEOFFROY ST. HILATRE. II7

the transformation of animal and vegetable species was less
effected by tlie action of the organism itself (by habit,
practice, use, or disuse of organs) than by the "monde
ambiant," that is, by the continual change of the outer
world, especially of the atmosphere. He conceives the
organism as passive, in regard to the vital conditions of the
outer world, while Lamarck, on the contrary, regards it
as active. Geoffroy thinks, for example, that birds origi-
nated from lizard-like reptiles, simply by a diminution of
the carbonic acid in the atmosphere, in consequence of which
the breathing process became more animated and energetic
through the increased proportion of oxygen in the atmosphere.
Thus there arose a higher temperature of the blood, an
increased activity of the nerves and muscles, and the scales
of the reptiles became the feathers of the birds, etc. This
conception is based upon a correct thought, but although
the change of the atmosphere, as well as the change of every
other external condition of existence, certainly effects
directly or indirectly the transformation of the organism,
yet this single cause is by itself too unimportant for such
effects to be ascribed to it. It is even less important than
practice and habit, upon which Lamarck lays too much
stress. Geoffroy 's chief merit consists in his having vindi-
cated the monistic conception of nature, the unity of
organic forms, and the deep genealogical connection of the
different organic types in the face of Cuvier's powerful
influence. I have already mentioned in the preceding
chapter (pp. 87, 88) the celebrated disputes between the two
great opponents in the Academy of Paris, especially the
fierce conflicts on the 22nd of February, and on the 19th of
July, in which Goethe took so lively an interest. On that

Il8 THE HISTOHY OF CKEATION.

occasion Cuvier remained the acknowledged victor, and
since tliat time very little, or rather nothing, more has he n
done in France to further the development of the Doctriue
of Filiation, and complete the monistic theory of development.
This is evidently to be ascribed principally to the repressive
influence exercised by Cuvier's great authority. Even at
the present day the majority of the French naturalists are
the disciples and blind followers of Cuvier. In no civilized
country of Europe has Darwin's doctrine had so little effect
and been so little understood as in France, so that in the
further course of our examination we need not take the
French naturalists into consideration. At most, there are
two distinguished botanists, among the recent French
naturalists, whom we may mention as having ventured
to express themselves in favour of the mutability and
transformation of species. These two men are Naudin
(1852) and Lecoq (1854^).

Having discussed the early services of German and
French nature-philosophy in establishing the doctrine of
descent, we turn to the third great country of Europe, to
free England, which during the last ten years has become
the chief seat and starting-point for the further working out
and definite establishment of the theory of development.
Englishmen, who now take such an active part in every
great scientific progress of humanity, and are the first to
promote the eternal truths of natural science, at the
beginning of the century took but little part in the conti-
nental nature-philosophy and its most important progress,
the Theory of Descent. Almost the only earlier English
naturalist whom we have here to mention is Erasmus
Darwin, the grandfather of the reformer of the Theory of

ERASMUS DARWIN, HERBERT, FREKE. IIQ

Descent. In 1795 he publislied, under the title of " Zoono-
mia," a scientific work in which he expresses views very
similar to those of Goethe and Lamarck, without, however,
then knowing anything about these two men. It is evident
that the Theory of Descent at that time pervaded the intel-
lectual atmosphere. Erasmus Darwin lays great stress upon
the transformation of animal and vegetable species by their
own vital action and by their becoming accustomed to
changed conditions of existence, etc. Next, W. Herbert, in
1822, expressed the opinion that species of animals and plants
are nothing but varieties which have become permanent.
In like manner Grant, in Edinburgh, in 1826, declared that
new species proceed from existing species by continued
transformation. In 1841 Freke maintained that all organic
beings must be descended from a single primitive type. In
1852 Herbert Spencer demonstrated minutely, and in a very
clear and philosophic manner, the necessity of the Doctrine
of Filiation, and established it more firmly in his excellent
" Essays," which appeared in 1858, and in his " Principles of
Biology," which was published at a later date. He has, at
the same time, the great merit of having applied the theory
of development to psychology, and of having shown that the
emotional and intellectual faculties could only have been
acquired by degrees and developed gradually. Lastly, we
have to mention that in 1859 Huxley, the first of English
zoologists, spoke of the Theory of Descent as the only
hypothesis of creation reconcilable with scientific physiology.
The same year produced the " Introduction to the Flora of
Tasmania," in which Hooker, the celebrated English
botanist, adopts the Theory of Descent, supporting it with
important observations of his own.

I20 THE HISTORY OF CEEATION.

All the naturalists and philosophers with whom we have
become acquainted in this brief historical survey, as men
adopting the Theory of Development, merely arrived at the
conception that all the different species of animals and
plants wliich at any time have lived, and still live, upon
the earth, are the gradually changed and transformed de-
scendants of one or some few original and very simple
prototypes, which latter arose out of inorganic matter by
spontaneous generation. But none of them succeeded in
placing this fundamental element of the doctrine of descent
in relation with some cause, nor in satisfactorily explaining
the transformation of organic species by the true demonstra-
tion of its mechanical antecedents. Charles Darwin was
the first who solved this most difiicult problem, and this
forms the broad gulf which separates him from his pre-
decessors.

The special merit of Charles Darwin is, in my opinion,
twofold: in the first place, the doctrine of descent, the
fundamental idea of which was already clearly expressed by
Goethe and Lamarck, has been developed by him much
more comprehensively, has been traced much more minutely
in all directions, and carried out much more strictly and
connectedly than by any of his predecessors ; and secondly,
he has established a new theory, which reveals to us the
natural causes of organic development, the acting causes
(causae efficientes) of organic form-production, and of the
changes and transformations of animal and vegetable species.
This is the theory which we call the Theory of Selection, or
more accurately, the Theory of Natural Selection (selectio
naturalis).

When we reflect that (with the few exceptions above men-

DARWIN S THEORY OF SELECTION. I 2 I

tioned) tlie whole science of Biology, before Darwin's time,
was elaborated in accordance with the opposite views, and
that almost all zoologists and botanists regarded the absolute
independence of organic species as a self-evident inference
from the results of all study of forms, we shall certainly not
lightly value the twofold merit of Darwin. The false
doctrine of the constancy and independent creation of
individual species had gained such high authority, was so
generally recognized, and was, moreover, so much favoured
by delusive appearances, accepted by superficial observation,
that, indeed, no small degi^ee of courage, strength, and
intelligence was required to rise as a reformer against its
omnipotence, and to dash to pieces the structure artificially
erected upon it. But, in addition to this, Darwin added to
Lamarck's and Goethe's doctrine of descent the new and
highly important principle of " natural selection."

We must sharply distinguish the two points — though this
is usually not done — first, Lamarck's Theory of Descent,
which only asserts that all animal and vegetable species are
descended from common, most simple, and spontaneously
generated prototypes; and secondly, Darwin's Theory of
Selection, which shows us why this progressive transfor-
mation of organic forms took place, and what causes, acting
mechanically, efiected the uninterrupted production of new
forms, and the ever increasing variety of animals and
plants.

Darwin's immortal merit cannot be justly estimated until
a later period, when the Theory of ]3evelopment, after over-
throwing all other theories of creation, will be recognized as
the supreme principle of explanation in Anthropology, and,
consequently, in all other sciences. At present, while in

122 THE HISTORY OF CREATION.

the hot contest for truth the name of Darwin is the watch-
word to the advocates of the natural theory of development,
his merits are inaccurately appreciated on both sides, for
some persons overestimate them as much as others under-
estimate them.

His merit is overestimated when he is regarded as the
founder of the Theory of Descent, or of the whole of the
Theory of Development. We have seen from the historical
sketch in this and the preceding chapters, that the Theory of
Development, as such, is not new; all philosophers who have
refused to be led captive by the blind dogma of a super-
natural creation, have been compelled to assume a. natural
development. But the Theory of Descent constituting the
specially biological part of the universal Theory of Develop-
ment, had already been so clearly expressed by Lamarck,
and carried out so fully by him to its most important con-
sequences, that we must honour him as the real founder of
it. Hence it is only the Theory of Selection, and not that
of Descent, which may be called Davwinisim ; but this is
in itself of so much importance, that its value can scarcely
be overestimated.

Darwin's merit is naturally underestimated by all his
opponents. But it is scarcely possible in this matter to
point to scientific opponents, who are entitled by profound
biological culture to pronounce an opinion. For among all
the works opposed to Darwin and the Theory of Descent yet
published, with the exception of that of Agassiz, not one
deserves consideration, much less refutation ; all have so
evidently been written either without thorough knowledge
of biological facts, or without a clear philosophical under-
standing of the question in hand. We need not trouble

LOUIS AGASSIZ ON DARWINISM. 12

n

ourselves at all about the attacks of theologians and other un-
scientific men, who really know nothing whatever of nature.

The only eminent scientific adversary who still remains
opposed to Darwin and the whole theory of development is
Louis Agassiz ; but the principle of his opposition in reality
deserves notice only as a philosophical curiosity. In a
French translation of his " Essay on Classification," ^ which
we have spoken of before, published in Paris in 1869,
Agassiz has most formally announced his opposition to
Darwinism, which he had previously expressed in many
ways. To this translation he has appended a treatise of
sixteen pages, bearing the title, " Le Darwinisme. Classifi-
cation de HaeckeL" This curious chapter contains the most
wonderful things; as, for example, "Darwin's idea is a
conception d priori. Darwinism is a burlesque of facts.
Science would renounce the claim which it has hitherto
possessed to the confidence of earnest minds if such sketches
were to be accepted as indications of a true progress." The
following passage, however, is the climax of this strange
polemic : " Darwinism shuts out almost the whole mass of
acquired knowledge in order to retain and assimilate to
itself that only which may serve its doctrine."

Surely this is what we may call turning the whole afiair
topsy-turvy ! The biologist who knows the facts must be
astounded at Agassiz's courage in uttering such sentences-
sentences without a word of truth in them, and which he
cannot himself believe ! The impregnable strength of the
Theory of Descent lies just in the fact that all biological
facts are explicable only through it, and that without it
they remain unintelligible miracles. All our "laborious
knowledge" in comparative anatomy and physiology — in

124 THE HISTORY OF CREATION.

embryology and pal£eontology — in the doctrine of the
geographical and topographical distribution of organisms,
etc., constitutes an irrefutable testimony to the truth of the
Theory of Descent.

In my General Morphology, especially in the sixth book
(in the General Phylogeny), I have minutely refuted Agassiz's
"Essay on Classification" in all essential points. The
twenty-fourth chapter I have devoted to a very detailed and
strictly scientific discussion of that section which Agassiz
himself considers the most important (the groups or cate-
gories of systematic zoology and botany), and have shown
that this part of his work is purely chimerical, without any
trace of real foundation. Agassiz takes good care not to
venture anywhere to touch upon my refutation, because,
forsooth, he is not in a position to produce anything
substantial against it. He fights not with arguments, but
with phrases. However, such opposition will not delay
the complete victory of the Theory of Development^ but
only accelerate it.

CHAPTER VT.

THEORY OF DEVELOPMENT ACCORDING TO LYELL

AND DARWIN.

Charles Lyell's Principles of Geology. — His Natural History of the Earth't-
Development. — Origin of the Greatest Effects through the Multiplication
of the Smallest Causes. — Unlimited Extent of Geological Periods. —
Lyell's Eefutation of Cuvier's History of Creation. — The Establishment
of the Uninterrupted Connection of Historical Development by Lyell
and Darwin. — Biographical Notice of Charles Darwin. — His Scientific
Works. — His Theory of Coral Reefs. — Development of the Theory of
Selection. — A Letter of Darwin's. — The Contemporaneous Appearance
of Darwin's and Alfred Wallace's Theory of Selection. — Darwin's Study
of Domestic Animals and Cultivated Plants. — Andreas Wagner's notions
as to the Special Creation of Cultivated Organisms for the good of
Man. — The Tree of Knowledge in Paradise. — Comparison between Wild
and Cultivated Organisms. — Darwin's Study of Domestic Pigeons. —
Importance of Pigeon Breeding.— Common Descent of all Kaces of
Pigeons.

During the thirty years, from 1830 until 1859, when
Darwin's work appeared, the ideas of creation introduced
by Cuvier remained predominant in the sciences of organic
nature. People rested satisfied with the unscientific assump-
tion, that in the course of the earth's history, a series of
inexplicable revolutions had periodically annihilated the
whole world of animals and plants, and that at the end of
each revolution, and the beginning of a new period, a new

120 THE HISTORY OF JEEATION.

enlarged, and improved edition of the organic population had
appeared. Although the number of these editions of creation
was altogether problematical, and in truth could not be fixed
at all, and although the numerous advances which, during
this time, were made in all the departments of zoology and
botany demonstrated more and more that Cuvier's hypo-
thesis was unfounded and untenable, and that Lamarck's
natural theory of development was nearer the truth, yet the
former maintained its authority almost universally among
biologists. This must, above all, be ascribed to the venera-
tion which Cuvier had acquired, and strikingly illustrates
how injurious to the progress of humanity a faith in
any definite authority may become. Authority, as Goethe
once admirably said, perpetuates the individual, which
as an individual should pass away, rejects and allows to
pass that which should be held fast, and is the main
obstacle to the advance of humanity.

It is only by having regard to the great weight of Cuvier's
authority, and to the mighty potency of human indolence,
which is with difficulty induced to depart from the broad
and comfortable way of everyday conceptions, and to enter
upon new paths not yet made easy, that we can comprehend
how it is that Lamarck's Theory of Descent did not gain its
due recognition until 1859, after Darwin had given it a new
foundation. The soil had long been prepared for it by the
works of Charles Lyell, another English naturalist, whose
views are of great importance for the natural history of
creation, and must accordingly here be briefly explained.

In 1830 Charles Lyell published, under the title of
" Principles of Geology," a work in which he thoroughly
reformed the science of Geology and the history of the earth's

LYELLS GEOLOGICAL DOCTRINES. 1 27

development, and effected this reform in a manner similar to
that in which, thirty years later, Darwin in his work reformed
the science of Biology. Lyell's great treatise, which radically
destroyed Cuvier's hypothesis of creation, appeared in the
same year in which Cuvier celebrated his triumph over the
nature-philosophy, and established his supremacy in the
domain of morphology for the following thirty years.
Whilst Cuvier, by his artificial hypothesis of creation and
his theory of catastrophes connected with it, directly ob-
structed the path of the theory of natural development,
and cut off all chance of a natural explanation, Lyell once
more opened a free road, and brought forward convincing
geological evidence to show that Cuvier's dualistic concep-
tions were as unfounded as they were superfluous. He
demonstrated that those changes of the earth's surface,
which are still taking place before our eyes, are perfectly
sufficient to explain everything we know of the development
of the earth's crust in general, and that it is superfluous and
useless to seek for mysterious causes in inexplicable revolu-
tions. He showed that we need only have recourse to the
hypothesis of exceedingly long periods of time in order to
explain the formation of the crust of the earth in the simplest
and most natural manner by means of the very same causes
which are still active. Many geologists had previously
imagined that the highest chains of mountains which rise on
the surface of the earth could owe their origin only to
enormous revolutions transforming a great part of the earth's
surface, especially to colossal volcanic eruptions. Such
chains of mountains as those of the Alps or the Cordilleras
were believed to have arisen direct from the fiery fluid of the
interior of the earth, through an enormous chasm in the

128 THE HISTOEY OF CREATION,

broken crust. Lyell, on the other hand, showed that we can
explain the formation of such enormous chains of mountains
quite naturally by the same slow and imperceptible risings and
depressions of the earth's surface which are still continually
taking place, and the causes of which are by no means
miraculous. Although these depressions and risings may
perhaps amount only to a few inches, or at most a few feet,
in the course of a century; still, in the course of some
millions of years they are perfectly sufficient to raise up the
highest chains of mountains, without the aid of mysterious
and incomprehensible revolutions. In hke manner, the
meteorological action of the atmosphere, the influence of rain
and snow, and, lastly, the breakers on the coasts, which by
themselves seem to produce an insignificant effect, must cause
the greatest changes if we only allow sufficiently long
periods for their action. The multiplication of the smallest
causes produces the greatest effects. Drops of water produce
a cavity in a rock.

I shall afterwards be obliged again to recur to the im-
measurable length of geological periods which are necessary
for this purpose, for, as we shall see, Darwin's theory, as
well as that of Lyell, renders the assumption of immense
periods absolutely necessary. If the earth and its organisms
have actually developed in a natural way, this slow and
gradual development must certainly have taken a length of
time which surpasses our powers of comprehension. But as
many men see in this very circumstance one of the principal
difficulties in the way of those theories of development, I beg
leave here to remark that we have not a single rational
ground for conceiving the time requisite to be limited in any
way. Not only many ordinary persons, but even eminent

NECESSITY OF LONG PERIODS. 1 29

naturalists, make it their chief objection to these theories,
that they arbitrarily claim too great a length of time : yet
the ground of objection is scarcely intelligible. For it is
absolutely impossible to see what can, in any way, limit us
in assuming long periods of time. We have long known,
even from the structure of the stratified crust of the earth
alone, that its origin and the formation of neptunic rocks
from water must have taken, at least, several millions of
years. From a strictly philosophical point of view, it makes
no difference whether we hypothetically assume for this pro-
cess ten millions or ten thousand billions of years. Before
us and behind us lies eternity. If the assumption of such
enormous periods is opposed to the feelings of many, I regard
this simply as the consequence of false notions which are
impressed upon us from our earliest youth concerning the
short history of the earth, which is said to embrace only
a few thousands of years. Albert Lange, in his " History
of Materialism,"^ has convincingly^ shown that from a
strictly philosophical point of view it is far less objec-
tionable in a scientific hypothesis to assume periods which
are too long than periods which are too short. Every
process of development is the more intelligible the longer it
is assumed to last. A short and limited period is the most
improbable.

I have no space here to enter minutely into Lyell's great
work, and will therefore mention only its most important
result, which is, that he completely refuted Cuvier's history
of creation with its mythical revolutions, and established in
its place the constant and slow transformation of the earth's
crust by the continued action of forces, which are still work-
ing on the earth's surface, viz. the movement of water and

I30 THE HISTORY OF CREATION.

the volcanic fluid of tlie interior of earth. Lyell thus demon-
strated a continuous and uninterrupted connection of the
whole history of the earth, and he proved it so irrefutably,
and established so convincingly the supremacy of the " ex-
isting causes," that is, of the causes which are still active
in the transformation of the earth's crust, that Geology in
a short time completely renounced Cuvier's hypothesis.

Now, it is remarkable that Palaeontology, the science of
petrifactions, so far as it was pursued by botanists and zoolo-
gists, remained apparently unaffected by this great progress
in geology. Biology still continued to assume repeated new
creations of the whole animal and vegetable kingdoms, at
the beginning of every new period of the earth's history,
although this hypothesis of individual creations, shoved into
the world one after the other, without the assumption of
Cuvier's cataclysms, became pure nonsense, and lost its
foundation. It is evidently perfectly absurd to assume a
distinct new creation of the whole world of animals and
plants at definite epochs, without the crust of the earth
itself experiencing any considerable general revolution.
And although this conception is most closely connected
with Cuvier's theory of catastrophes, still it prevailed when
the latter had been completely destroyed and abandoned.

It was reserved for the great English naturalist, Charles
Darwin, to remove this contradiction, and to show that the
organic beings of the earth have a history as continuous and
connected as the inorganic crust of the earth ; that animals
and plants have arisen from one another by as gradual a
transmutation as that by which the varying forms of the
earth's crust, the forms of the continents, and of the seas
surrounding and separating them, have arisen out of earlier

CHARLES ROBERT DARWIN. I31

and quite different forms. In this respect we may truly say
that in the domain of Zoology and Botany Darwin made
the same progress as Lyell, his great countryman, in the
domain of Geology. Both proved the uninterriqjted con-
nection of the historical development, and demonstrated a
gradual transmutation of the different conditions succeeding
one another.

The special merit of Darwin, as I have already remarked
in a preceding chapter, is twofold. In the first place, he has
treated the Theory of Descent, put forth by Lamarck and
Goethe, in a much more comprehensive manner, as a whole,
and carried it out in a much more connected manner, than
had been done by any one of his predecessors. Secondly,
he has established the causal foundation of this Theory of
Descent by the Theory of Selection, which is peculiarly his
own ; that is, he has demonstrated the acting causes of the
changes which the Theory of Descent simply stated, as facts.
The Theory of Descent, introduced into Biology in 1809, by
Lamarck, asserts that all the different species of animals
and plants are descended from a single or some few most
simple prototypes, produced by spontaneous generation.
The Theory of Selection, established in 1859 by Darwin,
shows us why this must be so ; it points out the acting
causes in a manner with which Kant would have been
delighted, and indeed, in the domain of organic nature,
Darwin has become the Newton whose advent Kant
thought himself entitled prophetically to deny.

Now, before we approach Darwin's theory, it will perhaps
be of interest to notice a few details as to the personal
character of this great naturalist, as to his life, and the
way in which he was led to form his doctrine. Charles

132 THE HISTOKY OF CREATION.

Robert Darwin was born at Shrewsbury, on the Severn,
on the 12th of February, 1809; therefore, at present he is
sixty-three years old. In his seventeenth year (1825) he
entered the University of Edinburgh, and two years later
Chi'ist's College, Cambridge. When scarcely twenty-two
years old, in 1831, he was invited to take part in a
scientific expedition which was sent out by England,
in order to survey accurately the southernmost point of
South America, and to examine several parts of the
South Seas. This expedition, like many other voyages of
inquiry fitted out in a praiseworthy manner by England,
had scientific objects, and at the same time was intended
to solve practical problems relating to navigation. The
vessel, commanded by Captain Fitzroy, appropriately bore
the symbolic name of the Beagle. The voyage of the
Beagle, which lasted five years, was of the highest im-
portance to the fall development of Darwin's genius ; for
in the very first year, when he set his foot on the soil
of South America, the outline of the doctrine of descent
dawned upon him. Darwin himself has described this
voyage in a work which is written in a very attractive
style, and the perusal of which I strongly recommend to
the reader. This book of travel, which lies far above the
usual average in interest, not only shows in a very charming
manner Darwin's amiable character, but we can in many
ways recognize the various steps by which he arrived at his
conceptions. The result of the voyage was, first, a large
scientific work, the zoological and geological portion of
which belong in a great measure to Darwin ; and secondly,
a celebrated work by him alone on Coral Reefs, which in
itself would have sufficed to secure to him a lasting reputa-

DARWIN S LIFE. 1 33

tion. It is Well known that the islands in the South Seas
consist for the most part of coral reefs, and are surrounded
by them. Formerly no satisfactory explanation could be
given of their different and remarkable forms, and of their
relation to those islands which are not formed of corals.
It was reserved for Darwin to solve this difficult problem,
for together with the constructive action of the coral
zoophytes, he assumed geological risings and depressions
of the bottom of the sea to account for the orisrin of
the different forms of reefs. Darwin's Theory of the
Origin of Coral Eeefs, like his later one as to the Origin of
Organic Species, is a theory which fully explains the
phenomenon, and for this purpose assumes only the simplest
natural causes, without hypothetically supporting it with
any unknown processes. Among the remaining works of
Darwin, I must not pass over his excellent monograph on
Cirrhipedia, a curious class of marine animals, which in
their outward appearance resemble mussels, and were
actually considered by Cuvier as Molluscs possessing two
shells, while in truth they belonged to the Crustacea (crabs).
The extraordinary hardships to which Darwin had been
exposed during his voyage in the Beagle had injured his
health to such a degree, that after his return home he was
obliged to withdraw from the restless turmoil of London life,
and since then has lived in quiet retirement on his estate at
Down, near Bromley, in Kent. This seclusion from the rest-
less activity of the great city certainly exercised a beneficial
influence upon Darwin, and it is probable that we owe to it,
at least partially, the formation of the Theory of Selection.
Undisturbed by the various engagements which in Londoi^
would have wasted his strength, he was enabled to concen-

134 THE HISTORY OF CREATION.

fcrate his attention upon the great problem to which his
mind had been turned dming his voyage in the Beagle. In
order to show what kind of observations during the voyage
principally gave rise to the fundamental idea of the Theory
of Selection, and in what manner he afterwards worked
it out, I shall insert here a passage from a letter which he
addressed to me on the 8th of October, 1864.

Letter from Charles Darivin to Haechel, Sth October, 1864.

" In South America three classes of facts were brought
strongly before my mind. Firstly, the manner in which
closely allied species replace species in going southward.
Secondly, the close affinity of the species inhabiting the
islands near South America to those proper to the con-
tinent. This struck me profoundly, especially the differ-
ence of the species in the adjoining islets in the Galopagos
Archipelago. Thirdly, the relation of the living Edentata
and Rodentia to the extinct species. I shall never forget
my astonishment when I dug out a gigantic piece of armour
like that of the living armadillo.

" Reflecting on these facts, and collecting analogous ones, it
seemed to me probable that allied species were descended
from a common parent. But for some years I could not
conceive how each form became so excellently adapted to
its habits of life. I then began sj^stematically to study
domestic productions, and after a time saw clearly that
man's selective power was the most important agent. I was
prepared, from having studied the habits of animals, to ap-
preciate the struggle for existence, and my work in geology
gave me some idea of the lapse of past time. Therefore,
when I ha])pened to read " Mai thus on Population," the idea

DABWIN S METHOD OF STUDY. 1 35

of natural selection flashed on me. Of all the minor points,
the last which I appreciated was the importance and cause
of the principle of divergence."

During the leisure and retirement in which Darwin lived
after his return, he occupied himself, as we see from this
letter, first and specially with the study of organisms in
their cultivated state ; that is, domestic animals and garden
plants. This was undoubtedly the most likely way to
arrive at the Theory of Selection. In this, as in all his
labours, Darwin proceeded with extreme care and accuracy.
With wonderful caution and self-denial, he published nothing
on this subject during a period of twenty-one years, from 1837
to 1858, not even a preliminary sketch of his theory, which
he had written as early as 1844. He was always anxious to
collect still more certain experimental proofs, in order to be
able to establish his theory in a complete form, and on the
broadest possible foundation of experience. While he was
thus aiming at the greatest possible perfection, which might
perhaps have led him never to publish his theory at all, he
was fortunately disturbed by a countryman of his, who,
independently of Darwin, had discovered the Theory of
Selection, and in 1858 sent its outlines to Darwin himself,
with the request to hand them to Lyell for publication in
some English journal. This was Alfred Wallace, one of the
boldest and most distinguished scientific travellers of modern
times. For many years Wallace had wandered alone in the
wilds of the Sunda Islands, in the dense primitive forests of
the Indian Archipelago ; and during this close and compre-
hensive study of one of the richest and most interesting
parts of the earth, with its great variety of animals and

136 THE HISTORY OF CREATION.

plants, he had arrived at exactly the same general views
regarding the origin of organic species as Darwin. Lyell
and Hooker, both of whom had long known Darwin's
work, now induced him to publish a short extract from his
manuscripts simultaneously with the manuscript sent him
by Wallace. They appeared in the Journal of the Linnean
Society, August, 1858.

Darwin's great work "On the Origin of Species," in
which the Theory of Selection is carried out in detail, ap-
peared in November, 1859. Darwin himself, however,
characterizes this book (of which a fifth edition appeared
in 1869, and the German translation by Bronn as early as
1860)^ as only a preliminary extract from a larger and
more detailed work, which is to contain a mass of facts in
favour of his theory, and comprehensive and experimental
proofs. The first part of the larger work promised by
Darwin appeared in 18C8, under the title, " The Variations
of Animals and Plants in the State of Domestication," and
has been translated into German by Victor Carus.^* It con-
tains a rich abundance of the most valuable evidence as
to the extraordinary changes of organic forms which man
can produce by cultivation and artificial selection. How-
ever much we are indebted to Darwin for this abundance of
convincing facts, still we do not by any means share the
opinion of those natm*alists who hold that the Theory of
Selection requires for its actual proof these further details.
It is our opinion that Darwin's first work, which appeared
in 1859, already contains sufficient proof The unassailable
strength of his theory does not lie in the immense amount
of individual facts that may be adduced as proofs, but in
the harmonious connection of all the great and general phe-

DARWIN S VARIOUS WORKS. 1 37

nomena of organic nature, which agree in bearing testimony
to the truth of the Theory of Selection.

Darwin, at first, intentionally did not notice the important
conclusion from his Theory of Descent, namely, the descent
of the human race from other mammals. It was not till
this highly important conclusion had been definitely estab-
lished by other naturalists as the necessary sequel of the
doctrine of descent, that Darwin himself expressly endorsed
it, and thereby completed his S3^stem. This was done in
the highly interesting work, "The Descent of Man, and
Sexual Selection," which appeared as late as 1871, and has
likewise been translated into German by Victor Carus.*^

The careful study which Darwin devoted to domestic
animals and cultivated plants was of the greatest import-
ance in establishing the Theory of Selection. The infinitely
varied changes of form which man has produced in these
domesticated organisms by artificial selection are of the
very highest importance for a right understanding of animal
and vegetable forms ; and yet this study has, down to the
most recent times, been most grossly neglected by zoologists
and botanists. Without entering upon the discussion of the
significance to be attached to the idea of species itself, they
have filled not only bulky volumes, but whole libraries,
with descriptions of individual species, and with most
childish controversies as to whether these species are good,
or tolerably good, and bad, or tolerably bad. If naturalists
instead of spending their time on these useless fancies had
duly studied cultivated organisms, and had examined the
transmutation of the living forms, instead of the individual
dead ones, they would not have been led captive so long by
the fetters of Cuvier's dogma. But as cultivated organisms

n8 THE HISTORY OF CREATION.

0

are so extremely inconvenient to the dogmatic conception
of the permanence of species, natm^alists to a great extent
intentionally did not concern themselves about them, and
even celebrated naturalists have often expressed the opinion
that cultivated organisms, domesticated animals and garden
plants, are artificial productions of man, and that their
formation and transformation could not decide anything
about the nature of species and about the origin of the
forms of species that live in a natural state.

This perverse view went so far that, for example, Andreas
Wagner, a zoologist of Munich, quite seriously made the
following ridiculous assertion: — ''Animals and plants in
their wild state have been called into being by the Creator
as distinctly different and unchangeable species ; but in the
case of domestic animals and cultivated plants this was not
necessary, because he formed them from the beginning for the
use of man. The Creator formed man out of a clod of earth,
breathed the living breath into his nostrils, and then created
for him the different useful domestic animals and garden
plants, among which he thought well to save himself the
trouble of distinguishing species." Unfortunately, Andreas
Wagner does not tell us whether the Tree of Knowledge
in Paradise was a " good " wild species, or, as a cultivated
plant, " no species " at all. As the Tree of Knowledge was
placed by the Creator in the centre of Paradise, we might
be inclined to believe that it was a highly favoured culti-
vated plant, and therefore no species at all. But since, on
the other hand, the fruit of the Tree of Knowledge was
forbidden to man, and since many men, as Wagner himself
clearly shows, have never eaten of the fruit, it was
evidently not created for the use of man, and therefore in

DOMESTICATED ORGANISMS. 139

all probability was a real species ! What a pity Wagner
has not given us any information about this important
and difficult problem !

Now, however ridiculous this view may appear to us, it
is only the logical sequence of a false view (which is widely
spread) of the special nature of cultivated organisms, and
one may occasionally hear similar objections from naturalists
of great reputation. I must most decidedly, and at once,
condemn this utterly false conception. It is the same per-
verseness which is committed by physicians who maintain
that diseases are artificial productions, and not natural
phenomena. It has been a work of hard labour to combat
this prejudice, and it is only in recent times that men have
generally adopted the view that diseases are nothing
but natural changes of the organisms, or really natural
phenomena of life, which are produced by changed and
abnormal conditions of existence. Disease, therefore, is not
a life beyond Nature's realm (vita prseter naturam), as the
early physicians used to say, but a natural life under con-
ditions which produce illness and threaten the body with
danger. Just in the same manner, cultivated organic forms
are not artificial works of man, but natural productions
which have arisen under the influence of peculiar conditions
of life. Man by his culture can never directly produce a
new organic form, but he can breed organisms under new
conditions of life, which are such as to influence and trans-
form them. All domestic animals and all garden plants
are originally descended from wild species, which have been
transformed by the peculiar conditions of culture.

A thorough comparison of cultivated forms (races and
varieties) with organisms not altered by cultivation (species

140 THE HISTOKY OF CEEATION.

and varieties), is of the utmost importance to the theory of
selection. What is most surprising in such a comparison is
the remarkably short time in which man can produce a
new form, and the high degree in which this form, pro-
duced by man, can deviate from the original form. While
wild animals and plants, one year after another, appear
to the zoologist and botanist approximately in the same
form, so as to have given rise to the false doctrine of the
constancy of species, domestic animals and garden plants,
on the other hand, display the greatest changes within a
few years. The perfection which gardeners and farmers
have attained in the art of selection now enables them, in
the space of a few years, arbitrarily to create entirely new
animal and vegetable forms. For this purpose it is only
necessary to keep and propagate the organism under the
influence of special conditions — which are capable of pro-
ducinof new formations —and even at the end of a few
generations new species may be obtained, which difier from
the original form in a much higher degree than so-called
good species in a wild state difier from one another. This
fact is extremely important, and we cannot lay sufficient
stress upon it. The assertion is not true that cultivated
forms descended from one and the same primary form do
not difier from one another as much as wild animal and
vegetable species difier among themselves. If we only make
comparisons, without prejudice, we can very easily perceive
that a number of races or varieties which have been derived
from a single cultivated form, within a short series of yeai-s,
differ from one another in a higher degree than so-called
good species (bonse species), or even different genera of one
family, in the wild state.

VARIETIES OF PIGEONS. I4I

In order to establish this extremely important fact as
firmly as possible by experiments, Darwin decided to make
a special study of the whole extent of variation in form in
a single group of domesticated animals, and for this purpose
he chose the domestic pigeons, which are in many respects
especially suited for such a study. For a long time he kept
on his estate all possible races and varieties of pigeons
which he was able to procure, and he was helped in this by
rich contributions from all parts of the world. He also
joined two London pigeon clubs, the members of which pas-
sionately, and with truly artistic skill, carry on the breeding
of the different forms of pigeons. Lastly, he formed con-
nections with some of the most celebrated pigeon-fanciers ;
so that he could command the richest experimental material.

The art of, and fancy for, pigeon breeding is very ancient.
Even more than 3,000 years before Christ, it was carried on
by the Egj^tians. The Romans, under the emperors, laid
out enormous sums upon the breeding of pigeons, and kept
accurate pedigrees of their descent, just as the Arabs keep
genealogical pedigrees of their horses, and the Mecklenburg
aristocracy of their own ancestors. In Asia, too, among
the wealthy princes, pigeon breeding was a very ancient
fancy ; in 1600, the court of Akber Khan possessed more
than 20,000 pigeons. Thus in the course of several centuries,
and in consequence of the various methods of breeding
practised in the different parts of the world, there has
arisen out of one single originally tamed form, an immense
number of different races and varieties, which in their most
divergent forms are extremely different from one another,
and are often curiously characterized.

One of the most striking races of pigeons is the well-

142 THE HISTOHY OF CREATION.

known fan-tailed pigeon, which spreads its tail like the pea-
cock, and carries a number of (from thirty to forty) feathers
placed in the form of radii, while other pigeons possess
much fewer tail feathers — generally twelve. We may here
mention that the number of feathers on the tails of birds is
considered by naturalists of great value as a systematic dis-
tinction, so that whole orders can thereby be distinguished.
For example, singing birds, almost without exception, possess
twelve tail feathers ; chirping birds (Strisores) ten, etc.
Several races of pigeons, moreover, are characterized by a
tuft of neck feathers, which form a kind of periwig ; others
by grotesque transformation of their beaks and feet, by pecu-
liar and often very remarkable decorations, as, for example,
skinny lappets, which develop on the head ; by a large
crop, which is formed by the gullet being strongly inclined
forward, etc. Remarkable, also, are the strange habits which
many pigeons have acquired ; for example, the turtle pigeons
and the trumpeters with their musical accomplishments, the
carriers with their topographical instinct. The tumblers
have the strange habit of ascending into the air in great
numbers, then turning over and falling down through the
air as if dead. The ways and habits of these endless races
of pigeons — the form, size, and colour of the individual parts
of their bodies, and their proportions, differ in a most
astonishing degree from one another ; in a much higher de-
gree than is the case with the so-called good species, or even
with the perfectly distinct genera, of wild pigeons. And
what is of the greatest importance, is the fact that these
differences are not confined to the external form, but extend
even to the most important internal parts ; there even occur
great modifications of the skeleton and of the muscular

VARIETIES OF RABBITS. 143

tissues. For example, we find great differences in the
number of vertebrae and ribs, in the size and shape of the
gaps in the breast-bones, in the size and shape of the merry-
thought, in the lower jaw, in the facial bones, etc. In short,
the bony skeleton, which morphologists consider a very
permanent part of the body, and which never varies to such
an extent as the external parts — shows such great changes,
that many races of pigeons might be described as special
genera, and this would doubtless be done if all these different
forms had been found in a wild and natural state.

How far the differences of the races of pigeons have been
carried is best shown by the fact that all pigeon breeders
are unanimously of opinion that each peculiar or specially
marked race of pigeons must be derived from a correspond-
ing wild original species. It is true every one assumes a
different number of original species. Yet Darwin has most
convincingly and acutely proved that all these pigeons,
without exception, must be derived from a single wild
primary species — from the blue rock-pigeon {Columha livia.)
In like manner, it can be proved of most of the domestic
animals and cultivated plants, that all the different races
are descendants of a single original wild species which has
been brought by man into a cultivated condition.

An example similar to that of the domestic pigeons is fur-
nished among mammals by our tame rabbit. All zoologists,
without exception, have long considered it proved that all
its races and varieties are descended from the common wild
rabbit, that is, from a single primary species. And yet the
extreme forms of these races differ to such a degree from
one another, that every zoologist, if he met with them in a
wild state, would unhesitatingly designate them not only as

144 THE HISTORY OF CREATION.

an entirely distinct "good species," but even as species of
entirely different genera of the Leporid family. Not only
does the colour, length of hair, and other qualities of the fur
of the different tame races of rabbits vary exceedingly, and
form extremely broad contrasts, but, what is still more im-
portant, the typical form of the skeleton and its individual
parts do so also, especially the form of the skull and the
jaw (which is of such importance in systematic arrange-
ment) ; further, the relative proportion of the length of the
ears, legs, etc. In all these respects the races of tame rabbits
avowedly differ from one another far more than all the dif-
ferent forms of wild rabbits and hares which are scattered
over all the earth, and are the recognized " good species " of
the genus Lepus, And yet, in the face of these clear facts, the
opponents of the theory of development maintain that the
wild species are not descended from a common prototype,
although they at once admit it in the case of the tame
races. With opponents who so intentionally close their
eyes against the clear light of truth, no further dispute can
be carried on.

While in this manner it aj)pears certain that the domestic
races of pigeons, of tame rabbits, of horses, etc., notwith-
standing the remarkable difference of their varieties, are
descended in each case from but one wild, so-called
" species " ; yet, on the other hand, it is certainly probable
that the great variety of races of some of the domestic ani-
mals, especially dogs, pigs, and oxen, must be ascribed to
the existence of several wild prototypes, which have become
mixed. It is, however, to be observed that the number of
these originally wild primary species is always much
smaller than that of the cultivated forms proceeding from

HYBRIDISM. 145

their mingling and selection, and naturally they were
originally derived from a single primary ancestor, com-
mon to the whole genus. In no case is each separate
cultivated race descended from a distinct wild species.

In opposition to this, almost all farmers and gardeners
maintain, with the greatest confidence, that each separate race
bred by them must be descended from a separate wild
primary species, because they clearly perceive the differences
of the races, and attach very high importance to the inherit-
ance of their qualities ; but they do not take into consider-
ation the fact that these qualities have arisen only by the
slow accumulation of small and scarcely observable changes.
In this respect it is extremely instructive to compare culti-
vated races with wild species.

Many naturalists, and especially the opponents of the
Theory of Development, have taken the greatest trouble to
discover some morphological or physiological mark, some
characteristic property, whereby the artificially bred and
cultivated races may be clearly and thoroughly distin-
guished from wild species which have arisen naturally.
All these attempts have completely failed, and have led
only with increasing certainty to the result, that such a
distinction is altogether impossible. I have minutely dis-
cussed this fact, and illustrated it by examples in my criti-
cism of the idea of species. (Gen. Morph. ii. 323-364.)

I may here briefly touch on yet another side of this
question, because not only the opponents, but even a few of
the most distinguished followers of Darwin — for example,
Huxley — have regarded the phenomena of hastard-breeding,
or hyhridism, as one of the weakest points of Darwinism.
Between cultivated races and wild species, they say, there

146 THE HISTORY OF CREATION.

exists this difference, that the former are capable of pro-
ducing fruitful bastards, but that the latter are not. Two
different cultivated races, or wild varieties of one species,
are said in all cases to possess the power of producing
bastards which can fruitfully mix with one another, or
with one of their parent forms, and thus propagate them-
selves ; on the other hand, two really different species, two
cultivated or wild species of one genus, are said never to be
able to produce from one another bastards which can be
fruitfully crossed with one another, or with one of their
parent species.

As regards the first of these assertions, it is simply re-
futed by the fact that there are organisms which do not
mix at all with their own ancestors, and therefore can
produce no fruitful descendants. Thus, for example, our
cultivated guinea-pig does not bear with its wild Brazilian
ancestor ; and again, the domestic cat of Paraguay, which is
descended from our European domestic cat, no longer bears
with the latter. Between different races of our domestic
dogs, for example, between the large Newfoundland dogs
and the dwarfed lap-dogs, breeding is impossible, even for
simple mechanical reasons. A particularly interesting in-
stance is afforded by the Porto-Santo rabbit (Lepus Hux-
leyi). In the year 1419, a few rabbits, born on board
ship of a tame Spanish rabbit, were put on the island of
Porto Santo, near Madeira. These little animals, there
being no beasts of prey, in a short time increased so enor-
mously that they became a pest to the country, and even
compelled a colony to remove from the island. They still
inhabit the island in great numbers ; but in the course of
four hundred and fifty years they have developed into a quite

FRUITFUL HYBRIDS. 1 47

peculiar variety — or if you will have it, into a "good
species " — which is distinguished by a peculiar colour, a rat-
like shape, small size, nocturnal life, and extraordinary wild-
ness. The most important fact, however, is that this new
species, which I call Lepus Huxleyi, no longer pairs with its
European parent rabbit, and no longer produces bastards
with it.

On the other hand, we now know of numerous examples
of fruitful genuine bastards ; that is, of mixings that have
proceeded from the crossing of two entirely different species,
and yet propagate themselves with one another as well as
with one of their parent species. A number of such bastard
species (species Hybridse) have long been known to botanists ;
for example, among the genera of the thistle (Cirsium), the
laburnum (Cytisus), the bramble (Rubus), etc. Among
animals also they are by no means rare, perhaps even very
frequent. We know of fruitful bastards which have arisen
from the crossing of two different species of a genus, as
among several genera of butterflies (Zygsena, Saturnia), the
family of carps, finches, poultry, dogs, cats, etc. One of the
most interesting is the hare-rabbit (Lepus Darwinii), the
bastard of our indigenous hare and rabbit, many genera-
tions of which have been bred in France, since 1850, for
gastronomic purposes. I myself possess such hybrids, the
products of pure in-breeding, that is, both parents of which
are themselves hybrids by a hare-father and a rabbit-mother.
I possess them through the kindness of Professor Conrad,
who has repeatedly made these experiments in breeding on
his estate. The half-blood hybrid thus bred, which I name
in honour of Darwin, appears to propagate itself through
many generations by pure in-breeding, just as well as any

I4S THE HISTORY OF CREATION.

genuine species. Although on the whole it is more like its
mother (rabbit), still in the formation of the ears and of the
hind-legs, it possesses distinct qualities of its father (hare).
Its flesh has an excellent taste, rather resembling that of a
hare, though the colour is more like that of a rabbit. But
the hare (Lepus timidus) and the rabbit (Lepus cuniculus)
are two species of the genus Lepus, so different that no
systematic zoologist will recognize them as varieties of one
species. Both species, moreover, live in such different ways,
and in their wild state entertain so great an aversion
towards one another, that they do not pair so long as they
are left free. If, however, the newly-born young ones of
both species are brought up together, this aversion is not
developed; they pair with one another and produce the
Lepus Darwinii.

Another remarkable instance of the crossing of different
species (where the two species belong even to different
genera !) is furnished by the fruitful hybrids of sheep and
goats which have for a long time been bred in Chili for in-
dustrial purposes. On what unessential circumstances in
the sexual mingling the fertility of the different species
depend, is shown by the fact that he-goats and sheep in
their mingling produce fruitful hybrids, while the ram and
she-goat pair very rarely, and then without result. The
phenomena of hybridism to which undue importance has
been erroneously attributed are thus utterly unmeaning, so
far as the idea of species is concerned. The breeding of
hybrids does not enable us, any more than other phenomena,
thoroughly to distinguish cultivated races from wild species ;
and this circumstance is of the greatest importance in the
Theory of Selection,

CHAPTER VII.

THE THEORY OF SELECTION (DARWINISM).

Darwinism (Theory of Selection) and Lamarclcism (Theory of Descent).—
The Process of Artificial Breeding.— Selection of the Different Indivi.
duals for After-breeding. — The Active Causes of Transmutation. — Change
connected with Food, and Transmission by Inheritance connected with
Propagation. — Mechanical Nature of these Two Physiological Functions.
— The Process of Natural Breeding : Selection in the Struggle for
Existence. — Malthus' Theory of Population. — The Proportion between
the Numbers of Potential and Actual Individuals of every Species of
Organisms. — General Struggle for Existence, or Competition to attain
the Necessaries of Life. —Transforming Force of the Struggle for
Existence.— Comparison of Natural and Artificial Breeding — Selection
in the Life of Man. — Military and Medical Selection.

It is, properly speaking, not quite correctly that the Theory
of Development, with which we are occupied in these pages,
is usually called Darwinism. For, as we have seen from
the historical sketch in the previous chapters, the most
important foundation of the Theory of Development — that
is, the Doctrine of Filiation, or Descent — ^had already been
distinctly enunciated at the beginning of our century, and
had been definitely introduced into science by Lamarck.
The portion of the Theory of Development which maintains
the common descent of all species of animals and plants from
the simplest common original forms might, therefore, in
8

150 THE HISTOEY OF CKEATION.

honour of its eminent founder, and with full justice, be called
La7)iavcldsin, if the merit of having carried out such a
principle is to be linked to the name of a single distinguished
naturalist. On the other hand, the Theory of Selection, or
breeding, might be justly called Dariuinism, being that por-
tion of the Theory of Development which shows us in what
way and why the different species of organisms have de-
veloped from those simplest primary forms. (Gen. Morph. ii
166).

It is true we find the first trace of an idea of natural
selection even forty years before the appearance of Darwin's
work. For in the year 1818 there was published a paper "On
a woman of the white race whose skin partly resembled that
of a negro," w^hich had been read before the Koyal Society
as early as 1813. Its author. Dr. W. C. Wells, states that
negroes and mulattoes are distinguished from the white race
by their immunity from certain tropical diseases. On this
occasion he remarks that all animals have a tendency to
change up to a certain degree, and that farmers, by availing
themselves of this tendency, and also by selection, improve
their domestic animals ; and then he adds, that what is done
in this latter case "by art, seems to be done with equal
efficiency, though more slowly, by nature, in the formation
of varieties of mankind fitted for the country which they
inhabit. Of the accidental varieties of man which would
occur among the first few and scattered inhabitants of the
middle regions of Africa, some one would be better fitted than
the others to bear the diseases of the country. This race
would consequently multiply, while the others would de-
crease ; not only from their inability to sustain the attacks
of disease, but from their incapacity of contending v/ith

NATURAL SELECTION. I51

their more vigorous neighbours. The colour of this vigorous
race I take for granted, from what has been already said,
would be dark. But the same disposition to form varieties
still existing, a darker and a darker race would in the course
of time occur ; and as the darkest would be the best fitted
for the climate, this would at length become the most pre-
valent, if not the only race, in the particular country in
which it had originated." He then extends these same
views to the white iuhabitants of colder climates. Although
Wells clearly expresses and recognizes the principle of
natural selection, yet it is applied by him only to the very
limited problem of the origin of human races, and not at
all to that of the origin of animal and vegetable species.
Darwin's great merit in having independently developed
the Theory of Selection, and having brought it to complete
and well merited recognition, is as little affected by the
earher and long forgotten remark of Wells, as by some other
fragmentary observations about natural selection made by
Patrick Mathew, and hidden in his book on "Timber for
Shipbuilding, and the Cultivation of Trees," which appeared
in 1831. The celebrated traveller, Alfred Wallace, who
developed the Theory of Selection independently of Darwin,
and had published.it in 1858, simultaneously with Darwin's
first contribution, likewise stands far behind his greater and
elder countryman in regard to profound conception, as
well as to extended application of the theory. In fact Dar-
win, by his extremely comprehensive and ingenious develop-
ment of the whole doctrine, has acquired a fair claim to see
the theory connected with his own name.

This Theory of Selection, Darwinism in its proper sense,
to the consideration of which we now turn our attention.

152 THE HISTORY OF CREATION.

rests essentially (as has already been intimated in the last
chapter) upon the comparison of those means which man
employs in the breeding of domestic animals and the culti-
vation of garden plants, with those processes which in
free nature, outside the cultivated state, lead to the coming
into existence of new species and new genera. We must
therefore, in order to understand the latter processes,
first turn to the artificial breeding by man, as was, in fact,
done by Darwin himself. We must inquire into the results
to which man attains by his artificial breeding, and what
means are aj)plied in order to obtain those results ; and we
must then ask ourselves, " Are there in nature similar forces
and causes acting similarly to those resorted to by man ? "

First, in regard to artificial breeding, we start from the
fact last discussed above, viz. that its products in some
cases differ from one another much more than the produc-
tions of natural breeding. It is a fact that races or varieties
often differ from one another in a much greater degree and
in much more important qualities than many so-called
species, or " good species," — nay, sometimes even more than
so-called "good genera" in their natural state. Compare,
for example, the different kinds of apples which the art
of horticulture has derived from one and the same
original apple-form, or compare the different races of horses
which their breeders have derived from one and the same
original form of horse, and it will be easily observed that
the differences of the most different forms are extreme] v
important, and much more important than the so-calleri
" specific differences," which are referred to by zoologists and
botanists when comparing wild forms for the purpose o^
distinguishing several so-called " good species."

THE GARDENERS SELECTION. 1 53

Now, by what means does man produce this extraordinarj^
difference or divergence of several forms which are proved
to be descended from the same primary form ? In order to
answer this question, let us follow a gardener who desires
to produce a new form of a plant, which is distinguished by
the beautiful colour of its flowers. He will first of all make
a selection from a great number of plants which are seed-
lings from one and the same parent. He will pick out
those plants which exhibit most distinctly the colour of
flower he desires. The colour of flowers is a very change-
able thing. Plants, for example, which as a rule have a
white flower, frequently show deviations into the blue or
red. Now, supposing the gardener wishes to obtain the red
colour in a plant usually producing white flowers, he will
very carefully, from among the many different individuals
which are the descendants of one and the same seed-plant, se-
lect those which most distinctly show a reddish tint, and sow
them exclusively, in order to produce new individuals of the
same kind. He would cast aside and no longer cultivate
the other seedlings which show a white or less distinct
red colour. He will propagate exclusively the individual
plants whose blossoms show the red most markedly, and he
will sow the seeds produced by these selected plants. From
the seedlings of this second generation, he will again care-
fully select those in which the red, which is now visible in
the majority of them, is most distinctly displayed. If
such a selection is carried on during a series of six or ten
generations, and if the flower which shows the deepest red
is most carefully selected, the gardener in the sixth or tenth
generation will obtain the desired plants with flowers of a
pure red.

154 THE HISTORY OF CHEATION.

Tlie farmer wishing to breed a special race of animals, for
example, a kind of sheep distinguished by particularly fine
wool, proceeds in the same manner. The only process
applied in the improvement of wool consists in this, that the
farmer with the greatest care and perseverance selects from
a whole flock of sheep those individuals which have the
finest wool. These only are used in breeding, and among
the descendants of these selected sheep, those again are
chosen which have the finest wool, etc. If this carefal
selection is carried on through a series of generations, the
selected breeding-sheep are in the end distinguished by a
wool which differs very strikingly from the wool of the
original parent, and this is exactly the advantage which
the breeder desired.

The difierences of the individuals that come into considera-
tion in this artificial selection are very slight. An ordinary
unpractised man is unable to discover the exceedingly
minute differences of individuals which a practised breeder
perceives at the first glance. The business of a breeder is
not easy; it requires an exceedingly sharp eye, great
patience, and an extremely careful manner of treating the
organisms to be bred. In each individual generation, the
differences of individuals are perhaps not seen at aU by the
uninitiated ; but by the accumulation of these minute
differences during a series of generations, the deviation from
the original form becomes in the end very gTeat. It becomes
so great that the artificially produced form may in the end
differ far more from the original form than do two so-
called "good species" in their natural state. The art of
breeding has now made such progress, that man can often at
discretion produce certain peculiarities in cultivated species

CARE REQUIRED IN SELECTION. 1 55

of animals and plants. To practised gardeners and farmers,
you may give distinct commissions, and say, for example,
I wish to have this species of plant with this or that colour,
and with this or that shape. Where breeding has reached
the perfection which it has attained in England, gardeners
and farmers are frequently able to furnish to order the
desired result within a definite period, that is, at the end of
a number of generations. Sir John. Sebright, one of the most
experienced English pigeon-breeders, could assert that in
three years he would produce any form of feather, but that
he required six years to obtain any desired form of the head
and beak. In the process of breeding the merino-sheep of
Saxony, the animals are three times placed on a table beside
one another, and most carefully compared and studied.
Each time only the best sheep with the finest wool are
selected, so that in the end, out of a great multitude, there
remain only some few animals, but their wool is exquisitely
fine, and only these last are used in breeding. We see,
therefore, that the causes through which, in artificial
breeding, great eflfects are produced, are unusually simple,
and these great efiects are obtained simply by accumulating
the diflferences which in themselves are very insignificant,
and become surprisingly increased by a continually repeated
selection.

Before we pass on to a comparison of this artificial with
natural breeding, let us see what natural quahties of the
organisms are made use of by the artificial breeder or
cultivator. We can trace all the different qualities which
here come into play to physiological fundamental qualities of
the organism, which are common to all animals and plants^
and are most closely connected with the functions of

156 THE HISTORY OF CREATION.

'propagation and nutrition. These two fundamental quali^
ties are transmissivity, or the capability of transmitting by
inheritance, and mutability, or the capability of adaptation.
The breeder starts from the fact that all the individuals of
one and the same species are different, though in a very
slight degree, a fact which is as true of organisms in a wild
as in a cultivated state. If you look about you in a forest
consisting of only a single species of tree, for example of
beech, you will certainly not find in the whole forest two
trees of this kind which are absolutely identical or perfectly
equal in the form of their branches, the number of their
branches and leaves, blossoms and fruits. Special differences
occur everywhere, just as in the case of men. There are
no two men who are absolutely identical, perfectly equal in
size, in the formation of their faces, the number of their
hairs, their temperament, character, etc. The very same is
true of individuals of all the different species of animals and
plants. It is true that in most organisms the difierences are
very trifling to the eye of the uninitiated. Everything
here essentially depends on the exercise of the faculty of
discovering these often very minute difierences of form. The
shepherd, for example, knows every individual of his fiock,
solely by accurately observing their features, while the
uninitiated are incapable of distinguishing at all the different
individuals of one and the same flock. This fact of the
individual difference is the extremely important foundation
on which the whole of man's power of breeding rests. If
individual differences did not exist everywhere, man would
not be able to produce a number of different varieties or
races from one and the same original stock We must, at
the outset, hold fast the principle that the phenomenon is

UNIVERSALITY OF VARIATION. 1 57

quite universal ; we must necessarily assume it even where,
with the imperfect capabilities of our senses, we are unable
to discover differences. Among the higher plants (the
phanerogams, or flower-plants), where the individual stocks
show such numerous differences in the number of branches or
leaves, and in the formation of the stem and branches, we
can almost always easily perceive these differences. But
this is not the case in the lower plants, such as mosses,
algse, fungi, and in most animals, especially the lower ones.
The distinction of all the individuals of one species is here,
for the most part, extremely difficult or altogether impossible.
' But there is no reason for ascribing individual differences only
to those organisms in which we can perceive them at once.
We may, on the contrary, with full certainty assume such
individuality as a universal quality of all organisms, and we
can do this all the more surely since we are able to trace the
mutability of individuals to the mechanical conditions of
nutrition. We can show that by influencing nutrition we
are able to produce striking individual differences where they
would not exist if the conditions of nutrition had not been
altered. The many complicated conditions of nutrition are
never absolutely identical in two individuals of a species.

Now, just as we see that the mutability or capability of
adaptation has a causal connection with the general rela-
tions of nutrition in animals and plants, so too we find the
second fundamental phenomenon of life, with which we are
here concerned, namely, the capability of transmitting by
inheritance, to have a direct connection with the phenome-
non of propagation. The second thing that a farmer or
gardener does in artificial breeding, after he has selected,
and has consequently availed himself of the mutability, is

I5S THE HISTORY OF CREATION.

to endeavour to hold fast and develop the modified forms by
Inheritance. He starts from the universal fact that children
resemble their parents, that "the apple does not fall far
from the tree." This phenomenon of Inheritance has hitherto
been scientifically examined only to a very small extent,
which may partly arise from the fact that the phenomenon
is of such everyday occurrence. Every one considers it
quite natural that every species should produce its like ;
that a horse should not suddenly produce a goose, or a goose
a frog. We are accustomed to look upon these everyday
occurrences of Inheritance as self-evident. But this phe-
nomenon is not so simply self-evident as it appears at
first sight, and in the examination of Inheritance the fact is
very frequently overlooked that the different descendants^
derived from one and the same parents, are in reality never
quite identical, and also never absolutely like the parents^
but are always slightly different. We cannot formulate the
principle of Inheritance, as "Like produces like," but we
must limit the expression to " Similar things produce
similar things." The gardener, as well as the farmer,
avails himself of the fact of Inheritance in its widest
form, and indeed with special regard to the fact that not
only those qualities of organisms are transmitted by
inheritance which they have inherited from their parents,
but those also which they themselves have acquired. This
is an important point upon which very much depends. An
organism can transmit to its descendants not only those
qualities of form, colour, and size which it has inherited
from its parents, but it can also transmit changes of these
qualities, which it has acquired during its own life through
the influence of outward circumstances, such as climate,
nourishment, training, etc.

INHERITANCE DUE TO CONTINUITY. 1 59

These are the two fundamental qualities of animals and
plants of which the breeder must avail himself in order to
produce new forms. The theoretical principle of breeding
is, indeed, extremely simple, but in detail the practical appli-
cation of this simple principle is difficult and immensely
complicated. A thoughtful breeder, acting according to
a definite plan, must understand the art of correctly esti-
mating, in every case, the general interaction between the
two fundamental qualities of heirship and mutability.

Now, if we examine the real nature of those two impor-
tant properties of life, we find that we can trace them, like
all physiological functions, to physical and chemical causes,
to the properties and the phenomena of motion of those
substances of which the bodies of animals and plants
consist. As we shall hereafter have to show in the more
accurate consideration of these two functions, the trans-
mission by Inheritance, if we express ourselves quite
generally, is essentially dependent upon the material con-
tinuity and partial identity of the matter in the producing
and produced organism, the parents and the child. In
every act of breeding a certain quantity of protoplasm or
albuminous matter is transferred from the parents to the
child, and along with it there is transferred the individually
'peculiar molecular motion. These molecular phenomena of
motion in the protoplasm, which call forth the phenomena
of life, and are their active and true cause, differ more or
less in all living individuals ; they are of infinite variety.

Adaptation, or transmutation is, on the other hand,
essentially the consequence of material influences, which the
substance of the organism experiences from the material
suiTounding it, — in the widest sense of the word from the

l6o THE HISTORY OF CEEATION.

conditions of life. The external influences of the latter are
communicated to the individual parts of the body by the
molecular processes of nutrition. In every act of Adaptation
the individual molecular motion of the protoplasm, peculiar
to each part, disturbs and modifies the whole individual, or
part of it, by mechanical, physical, or chemical influences.
The innate, inherited vital actions of the protoplasm — that is,
the molecular phenomena of motion of the smallest albu-
minous particles — are therefore more or less modified by it.
The phenomenon of Adaptation, or transmutation, depends
therefore upon the material influence which the organism
experiences from its surroundings, or its conditions of
existence; while the transmission by Inheritance is due
to the partial identity of the producing and produced
organism. These are the real, simple, mechanical founda-
tions of the artificial process of breeding.

Now Darwin asked himself. Does there exist a similar
process of selection in nature, and are there forces in nature
which take the place of man's activity in artificial selection ?
Is there a natural tendency among wild animals and plants
which acts selectingly, in a similar manner to the artificial
selection practised by the designing will of man? All
here depended upon the discovery of such a relation, and
Darwin succeeded in this so satisfactorily, that we con-
sider his theory of selection completely sufficient to
explain, mechanically, the origin of the wild species of
animals and plants. That relation which in free
nature influences the forms of animals and plants, by
selecting and transforming them, is called by Darwin
the " Struggle for Existence."

The " Struggle for Existence " has rapidly become a

THE STRUGGLE FOR EXISTENCE. l6l

watchword of the day. Yet this designation is, perhaps, in
many respects not very happily chosen, and the phenomena
might probably have been more accurately described as
" Competition for the Means of Subsistence^ For under the
name of "Struggle for Life," many relations are compre-
hended which properly and strictly speaking do not belong
to it. As we have seen from the letter inserted in the
last chapter, Darwin arrived at the idea of the " Struggle
for Existence " from the study of Malthus' book " On the
Conditions and the Consequences of the Increase of Popula-
tion." It was proved in that important work, that the
number of human beings, on the average, increases in a
geometrical progression, while the amount of articles of food
increase only in an arithmetical progression. This dispro-
portion gives rise to a number of inconveniences in the
human community, which cause among men a continual
competition to obtain the necessary means of life, which
do not suffice for all.

Darwin's theory of the struggle for life is, to a certain
extent, a general application of Malthus' theory of popula-
tion to the whole of organic nature. It starts from the
consideration that the number of possible organic indi-
viduals which might arise from the germs produced, is far
greater than the number of actual individuals whifch, in
fact, do simultaneously live on the earth's surface. The
number of possible or potential individuals is given us by
the number of the eggs and organic germs produced by
organisms. The number of these germs, from each of which,
under favourable circumstances, an individual might arise,
is very much larger than the number of real or actual
individuals — that is, of those that really arise from these

1 62 THE HISTORY OF CREATION.

germs, come into life, and propagate themselves. By far
the greater number of germs perish in the earliest stage of
life, and it is only some favoured organisms which manage to
develop, and actually survive the first period of early youth,
and finally succeed in propagating themselves. This import-
ant fact is easily proved by a comparison of the number of
eggs in a given species with the number of individuals which
exist of this species. These numerical relations show the
most striking contrast. There are, for example, species of
fowls which lay great numbers of eggs, and yet are among
the rarest of birds ; and the bird which is said to be the
commonest (the most widely spread) of all, the stormy petrel
{Procellaria glacialis), lays only a single egg. The relation
is the same in other animals. There are many very rare
invertebrate animals, which lay immense quantities of eggs ;
and others again which produce only very few eggs, and yet
are among the commonest of animals. Take, for example,
the proportion which is observed among the human tape-
worms. Each tape- worm produces within a short period
millions of eggs, while man, in whom these tape-worms are
lodged, forms a far smaller number of eggs, and yet for-
tunately there are fewer tape-worms than human beings.
In like manner, among plants there are many splendid
orchids, which produce thousands of seeds and yet are very
rare, and some kinds of asters (Compositse), which have but
few seeds, are exceedingly common.

This important fact might be illustrated by an immense
number of examples. It is evidently, therefore, not the
number of actually existing germs which indicates the num-
ber of individuals which afterwards come into life and
maintain themselves in life ; but rather the case is this,

THE STEUGGLE FOR EXISTENCE. 1 63

that the number of adult individuals is limited by other
circumstances, especially by the relations in which the
organism stands to its organic and inorganic surroundings.
Every organism, from the commencement of its existence,
struggles with a number of hostile influences : it struggles
against animals which feed on it, and to which it is thenatm-al
food, against animals of prey and parasites ; it struggles
against inorganic influences of the most varied kinds, against
temperature, weather, and other circumstances ; but it also
struggles (and this is much the most important !), above all,
against organisms most like and akin to itself. Every
individual, of every animal and vegetable species, is engaged
in the fiercest competition with every other individual of
the same species which lives in the same place with it. In
the economy of natui'e the means of subsistence are
nowhere scattered in abundance, but are very limited,
and far from sufficient for the number of organisms which
might develop from the germs produced. Therefore the
young individuals of most species of animals and vegetables
must have hard work in obtaining the means of subsist-
ence ; this necessarily causes a competition among them in
order to obtain the indispensable supplies of life.

This great competition for the necessaries of life goes on
everywhere and at all times, among human beings and
animals as well as among plants ; in the case of the latter
this circumstance, at first sight, is not so clearly apparent.
If we examine a field which is richly sown with wheat,
we can see that of the numerous young plants (perhaps
some thousands) which shoot up on a limited space, only a
very small proportion preserve themselves in life. A com-
petition takes place for the space of ground which each plant

164 THE HISTOKY OF CPvEATION.

requires for fixing its root, a competition for sunlight and
moisture. And in the same manner we find that, among all
animal species, all the individuals of one and the same species
compete with one another to obtain these indispensable
means of life, or the conditions of existence in the wide
sense of the word. They are equally indispensable to all,
but really fall to the lot of only a few — " Many are called,
but few are chosen." The fact of the great competition is
quite universal. You need only to cast a glance at human
society, where this competition exists everywhere, and in
all the different branches of human activity. Here, too,
a struggle is brought about by the free competition of the
different labourers of one and the same class. Here too,
as everywhere, this competition benefits the thing, or the
work, which is the object of competition. The greater and
more general the competition, the more quickly improve-
ments and inventions are made in the branch of labour, and
the higher is the grade of perfection of the labourers them-
selves.

The position of the different individuals in this struggle
for life is evidently very unequal. Starting from the
inequality of individuals, which is a recognized fact, we
must in all cases necessarily suppose that all the individuals
of one and the same species do not have equally favourable
prospects. Even at the beginning they are differently placed
in this competition by their different strengths and abilities,
independently of the fact that the conditions of existence
are different, and act differently at every point of the earth's
surface. We evidently have an infinite combination of in-
fluences, which, together with the original inequality of the
individuals during the competition for the conditions of

ADVANTAGEOUS CHARACTERS TRANSMITTED. 1 65

existence, favour some individuals and prejudice others. The
favoured individuals will gain the victory over the others,
and while the latter perish more or less early, without leav-
ing any descendants, the former alone will be able to survive
and finally to propagate the species. As, therefore, it is
clear that in the struggle for life the favoured individuals
succeed in propagating themselves, we shall (even as the re-
sult of this relation) perceive in the next generation differ-
ences from the preceding one. Some individuals of this
second generation, though perhaps not all of them, will,
by inheritance, receive the individual advantage by which
their parents gained the victory over their rivals.

But now — and this is a very important law of inheritance
— if such a transmission of a favourable character is con-
tinued through a series of generations, it is not simply trans-
mitted in the original manner, but it is constantly increased
and strengthened, and in a last generation it attains a
strength which distinguishes this generation very essentially
from the original parent. Let us, for example, examine a
number of plants of one and the same species which grow
together in a very dry soil. As the hairs on the leaves of
plants are very useful for receiving moisture from the air,
and as the hairs on the leaves are very changeable, the
individuals possessing the thickest hair on their leaves will
have an advantage in this unfavourable locality where the
plants have directly to struggle with the want of water, and
in addition to this have to compete with one another for
the possession of what little water there may be. These
' alone hold out, while the others possessing less hairy leaves
perish ; the more hairy ones will be propagated, and their
descendants will, on the average, be more distinguished by

1 66 THE HISTORY OF CREATION.

their thick and strong hairs than the individuals of the first
generation. If this process is continued for several genera-
tions in one and the same locality, there will arise at last
such an increase of this characteristic, such an increase of
the hairs on the surface of the leaf, that an entirely new
species seems to present itself. It must here be observed,
that in consequence of the interactions of all the parts of
every organism, generally one individual part cannot be
changed without at the same time producing changes in other
parts. If, for instance, in our imaginary example, the number
of the hairs on the leaves is greatly increased, a certain
amount of nourishment is thereby withdrawn from other
parts; the material which might be employed to form
flowers or seeds is diminished, and a smaller size of the
flower or seed will then be the direct or indirect consequence
of the struggle for life, which in the first place only pro-
duced a change in the leaves. Thus the struggle for life, in
this instance, acts as a means of selecting and transforming.
The struggle of the different individuals to obtain the
necessary conditions of existence, or, taking it in its widest
sense, the inter-relations of organisms to the whole of their
surroundings, produce mutations of form such as are pro-
duced in the cultivated state by the action of man's selection.
This agency will perhaps appear at first sight small and
insignificant, and the reader will not be inclined to concede
to the action of such relations the weight wliich it in reality
possesses. I must therefore find space in a subsequent
chapter to put forward further examples of the immense
and far-reaching power of transformation exhibited in
natui'al selection. For the present I will confine myself to
simply placing side by side the two processes of artificial

ARTIFICIAL AND NATURAL SELECTION. 1 67

and natural selection, and clearly explaining the agreement
and the differences of the two.

Both natural and artificial selection are quite simple
natural, mechanical relations of life, which depend upon the
interaction of two physiological functions, namely, on ^c^o^p-
tation and Inheritance, functions which, as such, must again
be traced to physical and chemical properties of organic
matter. The difference between the two forms of selection
consists in this : in artificial selection the will of man makes
the selection according to a ^^a'^, whereas in natural selection,
the struggle for life (that imiversal inter-relation of organ-
isms) acts tvithout a plan, but otherwise produces quite the
same result, namely, a selection of a particular kind of indi-
viduals for propagation. The alterations produced by artifi-
cial selection are turned to the advantage of those who make
the selection ; in natural selection, on the other hand, to the
advantage of the selected organism.

These are the most essential differences and agreements of
the two modes of selection ; it must, however, be further
observed that there is another difference, viz. in the duration of
time required for the two processes of selection. Man in his
artificial selection can produce very important changes in a
very short time, while in natural selection similar results are
obtained only after a much longer time. This arises from
the fact that man can make his selection with much greater
care. Man is able with the greatest nicety to pick out indi-
viduals from a large number, drop the others, and to employ
only the privileged beings for propagation, which is not the
case in natm^al selection. In natural conditions, besides the
privileged individuals which first succeed in propagating
themselves, some few or many of the less distinguished indi-

1 68 THE HISTORY OF CEEATION.

viduals will propagate themselves by the side of the former.
Moreover, man can prevent the crossing of the original and
the new form, which in natural selection is often unavoidable.
If such a crossing, that is, a sexual connection, of the new
variety with the original forms takes place, the offspring
thereby produced generally returns to the original character.
In natural selection, such a crossing can be avoided only
when the new variety by migration separates from the origi-
nal and isolates itself

Natural selection therefore acts much more slowly; it
requires much longer periods than the artificial process of
selection. But it is an essential consequence of this difier-
ence, that the product of artificial selection disappears much
more easily, and that the new form returns rapidly to the
earlier one, which is not the case in natural selection. The
new species arising from natural selection maintain them-
selves much more permanently, and return much less easily
to the original form, than is the case with products of artifi-
cial selection, and accordingly maintain themselves during a
much longer time than the artificial races produced by man.
But these are only subordinate differences, which are ex-
plained by the different conditions of natural and artificial
selection, and in reality are connected only with differences
in the duration of time. The nature of the transformation
and the means by which it is produced are entirely the
same in both artificial and natural selection. (Gen. Morph.
ii. 248).

The thoughtless and narrow-minded opponents of Darwin
are never tired of asserting that his theory of selection is
a groundless conjecture, or at least an hypothesis which has
3^et to be proved. That this assertion is completely un-

NECESSARY EFFICIENCY OF NATURAL SELECTION. 1 69

founded, may be perceived even from the outlines of the doc-
trine of selection which have just been discussed. Darwin
assumes no kind of unknown forces of nature, nor hypothetical
conditions, as the acting causes for the transformation of organic
forms, but solely and simply the universally recognized vital
activities of all organisms, which we term Inheritance and
Adaptation. Every naturalist acquainted with physiology
knows that these two phenomena are directly connected
with the functions of propagation and nutrition, and, like all
other phenomena of life, are purely mechanical processes of
nature, that is, they depend upon the molecular phenomena
of motion in organic matter. That the interaction of these
two functions effect a continual, slow transmutation of or-
ganic forms, is a necessary result of the struggle for exist-
ence. But this, again, is no more a hypothetical relation, nor
one requiring a proof, than is the interaction of Inheritance
and Adaptation. The struggle for life is a mathematical
necessity, arising from the disproportion between the limited
number of places in nature's household, and the excessive
number of organic germs. The origin of new species is
moreover greatly favoured by the active or passive migra-
tions of animals and plants, which takes place everywhere
and at all times, without being, however, entitled to rank
as necessary agents in the process of natural selection.

The origin of new species by natural selection, or, what
is the same thing, by the interaction of Inheritance and
Adaptation in the struggle for life, is therefore a mathe-
matical necessity of nature which needs no further proof
Whoever, in spite of the present state of our knowledge,
still seeks for proofs for the Theory of Selection, only
shows that he either does not thoroughly understand the

X70 THE HISTORY OF CREATION.

theory, or is not sufficiently acquainted with the biological
facts — ^has not the requisite amount of experimental know-
ledge in Anthropology, Zoology, and Botany.

If, as we maintain, natural selection is the great active
cause which has produced the whole wonderful variety of
organic life on the earth, all the interesting phenomena oi
human life must also be explicable from the same cause.
For man is after all only a most highly-developed vertebrate
animal, and all aspects of human life have their parallels, or,
more correctly, their lower stages of development in the
animal kingdom. The whole history of nations, or what is
called " Universal History," must therefore be explicable by
means of "natural selection," — must be a physico-chemical
process, depending upon the interaction of Adaptation and
Inheritance in the struggle for life. And this is actually
the case. We shall give further proofs of this later on.

It appears of interest here to remark that not only
natural selection, but also artificial selection exercises its
influence in many ways in universal history. A remark-
able instance of artificial selection in man, on a great
scale, is furnished by the ancient Spartans, among whom,
in obedience to a special law, all newly-born children
were subject to a careful examination and selection. All
those that were weak, sickly, or affected with any bodily
infirmity, were killed. Only the perfectly healthy and strong
children were allowed to live, and they alone afterwards pro-
pagated the race. By this means, the Spartan race was not
only continually preserved in excellent strength and vigour,
but the perfection of their bodies increased with every
generation. No doubt the Spartans owed their rare degree
of masculine strength and rou^'h heroic valour (for which

MILITARY SELECTION. I71

tliey are eminent in ancient history) in a great measure to
this artificial selection.

Many tribes also among the Red Indians of North
America (who at present are succumbing in the struggle
for life to the superior numbers of the white intruders, in
spite of a most heroic and courageous resistance) owe their
rare degree of bodily strength and warlike bravery to a
•similar careful selection of the newly-born children. Among
them, also, all children that are weak or affected with any
infirmity are immediately killed, and only the perfectly
strong individuals remain in life, and propagate the race.
That the race becomes greatly strengthened, in the course
of very many generations, by this artificial selection cannot
in itself be doubted, and is sufficiently proved by many well
known facts.

The opposite of this artificial selection of the wild Red-
skins and the ancient Spartans is seen in the individual
selection which is universally practised in our modern mili-
tary states, for the purpose of maintaining standing armies,
and which, under the name of military selection, we may
conveniently consider as a special form of selection. Un-
fortunately, in our day, militarism is more than ever promi-
nent in our so-called "civilization"; all the strength and
all the wealth of flourishing civilized states are squandered
on its development; whereas the education of the young,
and public instruction, which are the foundations of the
true welfare of nations and the ennobling of humanity, are
neglected and mismanaged in a most pitiable manner. And
this is done in states which believe themselves to be the
privileged leaders of the highest human intelligence, and to
stand at the head of civilization. As is well known, in

172 THE HISTORY OF CREATION.

order to increase the standing army as much as possible, all
healthy and strong young men are annually selected by a
strict system of recruiting. The stronger, healthier, and
more spirited a youth is, the greater is his prospect of being
killed by needle-guns, cannons, and other similar instru-
ments of civilization. All youths that are unhealthy, weak,
or affected with infirmities, on the other hand, are spared by
the "military selection," and remain at home during the
war, marry, and propagate themselves. The more useless,
the weaker, or infirmer the youth is, the greater is his pros-
pect of escaping the recruiting officer, and of founding a
family. While the healthy flower of youth dies on the
battle-field, the feeble remainder enjoy the satisfaction of
reproduction and of transmitting all their weaknesses and
infirmities to their descendants. According to the laws of
transmission by inheritance, there must necessarily follow in
each succeeding generation, not only a further extension,
but also a more deeply-seated development of weakness of
body, and what is inseparable from it, a condition of mental
weakness also. This and other forms of artificial selection
practised in our civilized states sufficiently explain the sad
fact that, in reality, weakness of the body and weakness of
character are on the perpetual increase among civilized
nations, and that, together with strong, healthy bodies, free
and independent spirits are becoming more and more scarce.
To the increasing enervation of modern civihzed nations,
which is the necessary consequence of military selection,
there is further added another evil The progress of modern
medical science, although still little able really to cure
diseases, yet possesses and practises more than it used to
do the art of prolonging life during lingering, chronic

MEDICAL SELECTION. 173

diseases for many years. Such ravaging evils as consump-
tion, scrofula, syphilis, and also many forms of mental dis-
orders, are transmitted by inheritance to a, great extent,
and transferred by sickly parents to some of their children,
or even to the whole of their descendants. Now, the longer
the diseased parents, with medical assistance, can drag on
their sickly existence, the more numerous are the descend-
ants who will inherit incurable evils, and the greater will
be the number of individuals, again, in the succeeding gene-
ration, thanks to that artificial "medical selection" who
will be infected by their parents with lingering, hereditary
disease.

If any one were to venture the proposal, after the ex-
amples of the Spartans and Kedskins, to kill, immediately
upon their birth, all miserable, crippled children to whom
with certainty a sickly life could be prophesied, instead of
keeping them in life injurious to them and to the race,
our so-called "humane civilization" would utter a cry of
indignation. But the same "humane civilization" thinks
it quite as it should be, and accepts without a murmur, that
at the outbreak of every war (and in the present state of
civilized life, and in the continual development of standing
armies, wars must naturally become more frequent) hundreds
and thousands of the finest men, full of youthful vigour, are
sacrificed in the hazardous game of battles. The same
" humane civilization " at present praises the abolition of
capital punishment as a " liberal measure ! " And yet
capital punishment for incorrigible and degi^aded criminals
is not only just, but also a benefit to the better portion of
mankind ; the same benefit is done by destroying luxuriant

weeds, for the prosperity of a well cultivated garden. As
9

174 THE HISTORY OF CREATION.

by a careful rooting out of weeds, light, air, and ground is
gained for good and useful plants, in like manner, by the
indiscriminate destruction of all incon^gible criminals, not
only would the struggle for life among the better portion of
mankind be made easier, but also an advantageous artificial
process of selection would be set in practice, since the possi-
bility of transmitting their injurious qualities by inheritance
would be taken from those degenerate outcasts.

Against the injurious influence of artificial military and
medical selection, we fortunately have a salutary counter-
poise, in the invincible and much more powerful influence
of natural selection, which prevails everywhere. For in
the life of man, as well as in that of animals and plants, this
influence is the most important transforming principle, and
the strongest lever for progTcss and amelioration. The
result of the struggle for life is that, in the long run, that
which is better, because more perfect, conquers that which
is weaker and imperfect. In human life, however, this
struo-ofle for life will ever become more and more of an
intellectual struggle, not a struggle with weapons of murder.
The organ which, above all others, in man becomes more
perfect by the ennobling influence of natural selection, is
the brain. The man with the most perfect understanding,
not the man with the best revolver, will in the long run be
victorious ; he will transmit to his descendants the qualities
of the brain which assisted him in the victory. Thus then
we may justly hope, in spite of all the efforts of retrograde
forces, that the progi^ess of mankind towards freedom, and
thus to the utmost perfection, will, by the happy influence
of natural selection, become more and more certain.

CHAPTER VIII.

TRANSMISSION BY INHERITANCE AND PROPAGATION.

Universality of Inheritance and Transmission by Inheritance. — Special
Evidences of the same. — Human Beings with four, six, or seven
Fingers and Toes. — Porcupine Men. — Transmission of Diseases, espe-
cially Diseases of the Mind. — Original Sin. — Hereditary Monarchies. —
Hereditary Aristocracy. — Hereditary Talents and Mental Qualities. —
Material Causes of Transmission by Inheritance. — Connection between
Transmission by Inheritance and Propagation. — Spontaneous Genera,
tion and Propagation. — Non-sexual or Monogonous Propagation. — Propa-
gation by Self-Division. — Monera and Amcebae. — Propagation by the
formation of Buds, by the formation of Germ-Buds, by the formation of
Germ-Cells. — Sexual or Amphigonous Propagation. — Formation of
Hermaphrodites. — Distinction of Sexes, or Gonochorism. — Virginal
Breeding, or Parthenogenesis. — Material Transmission of Peculiarities
of both Parents to the Child by Sexual Propagation. — Difference
between Transmission by Inheritance in Sexual and in Asexual
Propagation,

The reader has, in the last chapter, become acquainted
with natural selection according to Darwin's theory, as the
constructive force of nature which produces the different
forms of animal and vegetable species. By natural selection
we understand the interaction which takes place in the
struggle for life between the transmission by inheritance
and the mutahility of organisms, between two physiological
functions which are innate in all animals and plants,

176 THE HISTOKY OF CREATION.

and which may be traced to other processes of life — the
functions of propagation and nutrition. All the different
forms of organisms, which people are usually inclined to
look upon as the products of a creative power, acting for a
definite purpose, we, according to the Theory of Selection,
can conceive as the necessary productions of natural selec-
tion, working without a purpose, — as the unconscious inter-
action between the two properties of Mutability and
Hereditivity. Considering the importance which accordingly
belongs to these vital properties of organisms, we must
examine them a little more closely, and employ a chapter
with the consideration of Transmission by Inheritance.
(Gen. Morph. ii. 170-191).

Strictly speaking, we must distinguish between Heredi-
tivity (Transmissivity) and Inheritance (Transmission).
Hereditivity is the power of transmission, the capability of
organisms to transfer their peculiarities to their descendants
by propagation. Transmission by Inheritance, or Inheritance
simply, on the other hand, denotes the exercise of the
capability, the actual transmission.

Hereditivity and Transmission by Inheritance are such
universal, everyday phenomena, that most people do not
heed them, and but few are inclined to reflect upon the
operation and import of these phenomena of life. It is
generally thought quite natural and self-evident that every
organism should produce its like, and that children should
more or less resemble their parents. Heredity is usually
only taken notice of and discussed in cases relating
to some special peculiarity, which appears for the first
time in a human individual without having been inherited,
and then is transmitted to his descendants. It shows

INHERITANCE OF MONSTROSITIES. 177

itself in a specially striking manner in the case of certain
diseases, and in unusual and irregular (monstrous) devia-
tions from tlie usual formation of the body.

Amono: these cases of the inheritance of monstrous devi-
ations, those are specially interesting which consist in an
abnormal increase or decrease of the number five in the fin-
gers or toes of man. It is not unfrequently observed in
families through several generations, that individuals have six
fingers on each hand, or six toes on each foot. Less frequent
is the number of four or seven fingers or toes. The unusual
formation arises at first from a single individual who, from
unkno^vn causes, is born with an excess of the usual number
of fingers and toes, and transmits these, by inheritance, to a
portion of his descendants. In one and the same family it
has happened that, throughout three, four, or more genera-
tions, individuals have possessed six fingers and toes. In a
Spanish family there were no less than forty individuals
distinguished by this excess. The transmission of the sixth
finger or toe is not permanent or enduring in all cases, be-
cause six-fingered people always intermarry again with
those possessing five fingers. If a six-fingered family were
to propagate by pure in-breeding, if six-fingered men were
always to marry six-fingered women, this characteristic
would become permanent, and a special six-fingered human
race would arise. But as six-fingered men usually marry
five-fingered women, and vice versd, their descendants for
the most part show a very mixed numerical relation, and
finally, after the course of some generations, revert again to
the normal number of five. Thus, for example, among eight
children of a six-fingered father and a five-fingered mother,
two children may have on both hands and feet six fingers

lyS THE HISTOr.Y OF CREATION.

and toes, four children may have a mixed number, and two
children may have the usual number of five on both hands
and feet. In a Spanish family, each child except the
youngest had the number six on both hands and feet; the
youngest, only, had the usual number on both hands and feet,
and the six-fingered father of the child refused to recognize
the last one as his own.

The power of inheritance, moreover, shows itself very
strikingly in the formation and colour of the human skin
and hair. It is well known how exactly the nature of the
complexion in many families — for instance, a peculiar soft
or rough skin, a peculiar luxuriance of the hair, a peculiar
colour and largeness of the eyes — is transmitted through
many generations. In like manner, peculiar local growths
or spots on the skin, the so-called moles, freckles, and other
accumulations of pigment which appear in certain places, are
frequently transmitted through several generations so
exactly, that in the descendants they appear on the same
spots on which they existed in the parents. The porcupine
men of the Lambert family, who lived in London last cen-
tury, are especially celebrated. Edward Lambert, bom in
1717, was remarkable for a most unusual and monstrous
formation of the skin. His whole body was covered with a
horny substance, about an inch thick, which rose in the
form of numerous thorn-shaped and scale-like processes,
more than an inch long. This monstrous formation of the
outer skin, or epidermis, was transmitted by Lambert to his
sons and grandsons, but not to his granddaughters. The
transmission in this instance remained in the male line, as
is often the case. In like manner, an excessive develop-
ment of fat in certain parts of the body is often transmitted

TKANSMISSIOX OF MENTAL QUALITIES. 1 79

only in tlie female line. I scarcely need call to mind how
exactly the characteristic formation of the face is transmitted
by inheritance ; sometimes it remains within the male, some-
times within the female line ; sometimes it is blended in both.
The phenomena of transmission by inheritance of patho-
logical conditions, especially of the different forms of human
diseases, are very instructive and generally known. Diseases
of the respiratory organs, the glands, and of the nervous
system, are specially liable to be transmitted by inheritance.
Very frequently there suddenly appears in an otherwise
healthy family a disease until then unknown among them ;
it is produced by external causes, by conditions of life causing
disease. This disease, brought about in an individual by
external cause, is propagated and transmitted to his descend-
ants, and some or all of them then suffer from the same
disease. In case of diseases of the lungs, for instance in
consumption, this sad transmission by inheritance is well
known, and it is the same with diseases of the liver, with
syphilis, and diseases of the mind. The latter are specially
interesting. Just as peculiar characteristic features of man
— pride, ambition, frivolity, etc.— are transmitted to the
descendants strictly by inheritance, so too are the peculiar
abnormal manifestations of mental activity, which are
usually called fixed ideas, despondency, imbecility, and
generally "diseases of the mind." This distinctly and
irrefragably shows that the soul of man, just as the soul
of animals, is a purely mechanical activity, the sum of
the molecular phenomena of motion in the particles of the
brain, and that it is transmitted by inheritance, together
with its substratum, just as every other quality of the body
is materially transmitted by ]:)ropagation.

l8o THE HISTOEY OF CEEATION.

When this exceedingly important and undeniable fact is
mentioned, it generally causes great offence, and yet in
reality it is silently and universally acknowledged. For
upon what else do the ideas of " hereditary sin," " hereditary
wisdom," and " hereditary aristocracy," etc., rest than upon
the conviction that the quality of the human mind is trans-
mitted by propagation — that is, by a purely material pro-
cess— through the body, from the parents to the descendants?
The recognition of this great importance of transmission by
inheritance is shown in a number of human institutions, as
for example, among many nations in the division into castes,
such as the castes of warriors, castes of priests, and castes of
labourers, etc. It is evident that the institution of such
castes originally arose from the notion of the great import-
ance of hereditary distinctions possessed by certain families,
which it was presumed would always be transmitted
by the parents to the children. The institution of an
hereditary aristocracy and an hereditary monarchy is
to be traced to the notion of such a transmission of special
excellencies. However, it is unfortunately not only virtues,
but also vices that are transmitted and accumulated by
inheritance ; and if, in the history of the world, we compare
the different individuals of the different dynasties, we shall
everywhere find a great number of proofs of the transmission
of qualities by iidieritance, but fewer of transmissions of
virtues than of vices. Look only, for example, at the Roman
emperors, at the Julii and the Claudii, or at the Bourbons in
France, Spain, and Italy !

In fact, scarcely anywhere could we find such a number
of striking examples of the remarkable transmission of
bodily and mental features by inheritance, as in the history

li^SANITY IN ROYAL FAMILIES. l8l

of the reigning houses in hereditary monarchies. This is
specially true in regard to the diseases of the mind pre-
viously mentioned. It is in reigning families that mental
disorders are hereditary in an unusual degree. Thus Esquirol,
distinguished for his knowledge of mental diseases, proved
that the number of insane individuals in the reigning houses
was, in proportion to the number among the ordinary popu-
lation, as 60 to 1 ; that is, that disorders of the brain occur
60 times more frequently in the privileged families of the
ruling houses than among ordinary people. If equally
accurate statistics were made of the hereditary nobility,
the result would probably be that here also we should find
an incomparably larger contingent of mental diseases than
among the common, ignoble portion of mankind. This
phenomenon can scarcely astonish us if we consider what
injury these privileged castes inflict upon themselves by
their unnatural, one-sided education, and by their artificial
separation from the rest of mankind. By this means many
dark sides of human nature are specially developed and, as
it were, artificially bred, and, according to the laws of trans-
mission by inheritance, are propagated through series of
generations with ever-increas'ng force and dominance.

It is sufficiently obvious from the history of nations how
in successive generations of many dynasties, for example,
of the princes of Saxon Thuringia and of the Medici, the
noble solicitude for the most perfect human accomplish-
ments in science and art were retained and transmitted
from father to son ; and how, on the other hand, in many
other dynasties, for centuries a special partiality for the
profession of war, for the oppression of human freedom, and
for other rude acts of violence, have been hereditary. In like

1 82 THE HISTORY OF CKEATION.

manner talents for special mental activities are transmitted in
many families for generations, as, for instance, talent for
mathematics, poetry, music, sculpture, the investigation of
natm-e, philosophy, etc. In the family of Bach there have
been no less than twenty-two eminent musicians. Of course
the transmission of such peculiarities of mind depends upon
the material process of reproduction, as does the transmission
of mental qualities in general. In this case again, the vital
phenomenon, the manifestation of force (as everywhere in
nature), is directly connected with definite relations in the
admixture of the material components of the organism. It
is this definite proportion and molecular motion of matter
which is transmitted by generation.

Now, before we examine the numerous, and in some cases
most interesting and important, laws of transmission by
inheritance, let us make ourselves acquainted with the
actual nature of the process. The phenomena of transmis-
sion by inheritance are generally looked upon as something
quite mysterious, as peculiar processes which cannot be
fathomed by natural science, and the causes and actual
nature of which cannot be understood. It is precisely in
such a case that people very generally assume supernatural
influences. But even in the present state of our physiology
it can be proved with complete certainty that all the
phenomena of inheritance are entirely natural processes,
that they are produced by mechanical causes, and that they
depend on the material phenomena of motion in the bodies
of organisms, which we may consider as a part of the
phenomena of propagation. All the phenomena of Heredity
and the laws of Transmission by Inheritance can be traced
to the material process oi Propagation.

THE PROCESS OF KEPKODUCTION. 1 83

Every organism, every living individual, owes its exist-
ence either to an act of unparental or Spontaneous Genera-
tion (Generatio Spontanea Archigonia), or to an act of
Parental Generation or Propagation (Generatio Parentalis,
Tocogonia), In a future chapter we shall have to consider
Spontaneous Generation, or Archigony. At present we must
occupy ourselves with Propagation, or Tocogony, a closer
examination of which is of the utmost importance for under-
standing transmission by inheritance. Most of my readers
probably only know those phenomena of Propagation which
are seen universally in the higher plants and animals, the
processes of Sexual Propagation, or Amphigony. The pro-
cesses of Non-sexual Propagation, or Monogony, are much less
generally known. Tlie latter, however, are far more suited
to throw light upon the nature of transmission by inherit-
ance in connection with propagation.

For this reason, we shall first consider only the phe-
nomena of non-sexual or monogonic propagation (Mono-
gonia). This appears in a variety of different forms, as for
example, self-division, formation of buds, the formation of
germ-cells or spores (Gen. Morph. ii. 36-58). It will
be most instructive, first, to examine the propagation of
the simplest organisms known to us, which we shall have
to return to later, when considering the question of
spontaneous generation. These very simplest of all
organisms yet known, and which, at the same time, are the
simplest imaginable organisms, are the Monera living in
water ; they are very small living corpuscles, which, strictly
speaking, do not at all deserve the name of organism.
For the designation " organism," appHed to living creatures,
rests upon the idea that every living natural body is com-

184 THE HISTORY OF CHEATIOK.

posed of organs, of various parts, which fit into one anothef
and "work together (as do the different parts of an artificial
machine), in order to produce the action of the whole,.
During late years we have become acquainted with Monera,
organisms which are, in fact, not composed of any organs at
all, but consist entirely of shapeless, simple, homogeneous
matter. The entire body of one of these Monera, during
life, is nothing more than a shapeless, mobile, little lump of
mucus or slime, consisting of an albuminous combination
of carbon. Simpler or more imperfect organisms we cannot
possibly conceive.

The first complete observations on the natural history
of a Moneron (Protogenes primordialis) were made by me
at Nice, in 1864. Other very remarkable Monera I
examined later (18G6) in Lanzarote, one of the Canary
Islands, and in 1867 in the Straits of Gibraltar. The com-
plete histoiy of one of these Monera, the orange -red
Protomyxa aurantiaca, is represented in Plate I, and its
explanation is given in the Appendix. I have found
some curious Monera also in the North Sea, off the
Norweo'ian coast, near Bero-en. Cienkowski has described
(1865) an interesting Moneron from fresh waters, under the
name of Vaonpyrella. But perhaps the most remarkable of
all Monera was discovered by Huxley, the celebrated
English zoologist, and called Bathyhius Hceckelii, " Bathy-
bius " means, living in the deep. This wonderful organism
lives in immense depths of the ocean, which are over
12,000 — indeed, in some parts 24,000 feet below the surface,
and which have become known to us within the last ten
years, through the laborious investigations made by the
English. There, among the numerous Polythalamia and

Life liistpry of a simplest organism

PI. I.

^

.1 i

10.

.'),

fejt-

//.

/7.

/.■;.

J

I ,*^:

/:^

U.

Jji.

E.Haeckel del.

Frotom vxa cuira}iii/ica .

Laoesse sc.

DESCRIPTION OF A MONERON. 1 85

Radiolarla which inhabit the fine calcareous mud of these
abysses, the Bathybius is found in great quantities, some-
times in the shape of roundish, formless lumps of mucus,
sometimes in the form of a network of mucus, covering
fragments of stone and other objects. Small particles of
chalk are frequently embedded in these mucous gelatinous
masses, and are, perhaps, products of their secretion. The
entire body of this remarkable Bathybius consists solely of
shapeless plasma, or protoplasm, as in the case of the other
Monera— 'that is, it consists of the same albuminous com-
bination of carbon, which in infinite modifications is found
in all organisms, as the essential and never-failing seat of
the phenomena of life. I have given a detailed description
and drawing of the Bathybius and other Monera in my
"Monographic der Moneren," 1870,^^ from which the draw-
ing in Fig. 9 is taken.

In a state of rest most Monera appear as small globules of
mucus or slime, invisible, or nearly so, to the naked eye ;
they are at most as large as a pin's head. When the
Moneron moves itself, there are formed on the upper surface
of the little mucous globule, shapeless, fingerlike processes,
or very fine radiated threads ; these are the so-called false
feet, or pseudopodia. The false feet are simple, direct
continuations of the shapeless albuminous mass, of wdiich
the whole body consists. We are unable to perceive
different parts in it, and we can give a direct proof of the
absolute simplicity of the semi-fluid mass of albumen, for
with the aid of the microscope we can follow the Moneron
as it takes in nourishment. When small particles suited
for its nourishment — for instance, small particles of decayed
organic bodies or microscopic plants and infusoria — acci-

i86

THE HISTORY OF CREATION.

/

dentally come into contact with tlie Moneron, tliey remain
hanging to the sticky semi-fluid globule of mucus, and
here create an irritation, which is followed by a strong afflux
of the mucous substance, and, in consequence, they become
finally completely inclosed by it, or are drawn into the
body of the Moneron by displacement of the several albu-
minous particles, and are there digested, being absorbed by
simple difi*usion (endosmosis).

Just as simple as the process of nutrition is the propaga-
tion of these primitive creatures, which in reality we can
neither call animals nor plants. All Monera propagate
themselves only in an asexual manner by monogony ; and
in the simplest case, by that kind of monogony which we
place at the head of the different forms of propagation, that
is, by self-division. When such a little globule, for example
a Protamoeba or a Protogenes, has attained a certain size
by the assimilation of foreign albuminous matter, it falls
into two pieces ; a pinching in takes place, contracting the
middle of the globule on all sides, and finally leads to the
separation of the two halves (compare Fig. 1.). Each half

Fig. 1. — Propagation of tlie simplest organism, a Moneron, by self. division.
A. The entire Moneron, a Protamoeba. B. It falls into two halves by a
contraction in the middle. C. Each of the two halves has separated from
the other, and now represents an independent individual.

PROPAGATION OF AlONEKA, 187

then becomes rounded off, and now appears as an indepen-
dent individual, which commences anew the simple course
of the vital phenomena of nutrition and propagation. In
other Monera (Vampyrella), the body in the process of
propagation does not fall into two, but into four equal pieces,
and in others, again (Protomonas, Protomyxa, Myxastrum),
at once into a number of small globules of mucus, each of
which again, by simple growth, becomes like the parent
body. Here it is evident that the process of propagation
is nothing but a groivtk of the organism beyond its own
individual lir)%it of size.

The simple method of propagation of the Moneron by self-
division is, in reality, the most universal and most widely
spread of all the different modes of propagation ; for by the
same simple process of division, cells also propagate them-
selves. Cells are those simple organic individuals, a large
number of which constitute the bodies of most organisms,
the human body not excepted. With the exception of the
organisms of the lowest order, which have not even the
perfect form of a cell (Monei-a), or during life only repre-
sent a single cell (many Protista and single-celled plants),
the body of every organic individual is composed of a great
number of cells. Every organic cell is to a certain degree
an independent organism, a so-called " elementary organism,"
or an " individual of the first order." Every higher organ-
ism is, in a measure, a society or a state of such variously
shaped elementary individuals, variously developed by divi-
sion of labour. ^^ Originally every organic cell is only a
single globule of mucus, like a Moneron, but differing from
it in the fact that the homogeneous albuminous substance
has separated itself into two different parts, a firmer albu-

iSS

THE HISTORY OF CREATION.

minous body, the cell-kernel (nucleus), and an external,
softer albuminous body, the cell-substance or body (proto-
plasma). Besides this, many cells later on form a third
(frequently absent) distinct part, inasmuch as they cover
themselves with a capsule, by exuding an outer pellicle or
cell-meonbrane (membrana). All other forms of cells, besides
these, are of subordinate importance, and are of no further
interest to us here.

Every organism composed of many cells was originally a
single cell, and it becomes many-celled owing to the fact
that the original cell propagates itself by self-division, and
that the new individual cells originating in this manner
remain together, and by division of labour form a commu-
nity or a state. The forms and vital phenomena of all many-
celled organisms are merely the effect or the expression of all
the forms and vital phenomena of all the individual cells of
which they are composed. The egg, from which most ani-
mals and plants are developed, is a simple cell.

Fig. 2. — PropaQfation of a single-celled orGranism, Amoeba sphEerococctis,
by self-division. A. The enclosed Amoeba, a simple globular cell consisting of
a lump of protoplasm (c), which contains a kernel (&) and a kernel speck (a),
and is surrounded by a cell-membrane or capsule. B. The free Amoeba, which
has burst and left the cyst or cell-membrane. C. It begins to divide by its
kernel forming two kernels, and by the celLsubstance between the two
becoming contracted. D. The division is completed by the cell-substance
likewise falling into two halves (Da and Db).

SELF-DIVISION OF CELLS. 1 89

The single-celled organisms, that is, those which during
life retain the form of a single cell, for example the Amoebse,
as a rule propagate themselves in the simplest way by self-
division. This process differs from the previously described
self-division of the Moneron only in the fact that at the
commencement the firmer cell-kernel (nucleus) falls into two
halves, by a pinching in at its middle. The two young ker-
nels separate from each other and act now as two distinct
centres of attraction upon the surrounding softer albu-
minous matter, that is, the cell-substance (protoplasma). By
this process finally the latter also divides into two halves, and
there now exist two new cells, which are like the mother cell.
If the cell was surrounded by a membrane, this either does
not divide at all, as in the case of egg-cleavage (Fig. 3, 4), or it
passively follows the active pinching in of the protoplasm ;
or, lastly, every new cell exudes a new membrane for itself

The non-independent cells which remain united in commu-
nities or states, and thus constitute the body of higher or-
ganisms, are propagated in the same manner as are inde-
pendent single-celled organisms, for example, Amoeba (Fig. 2).
Just as in that case, the cell with which most animals
and plants commence their individual existence, namely, the
egg, multiplies itself by simple division. When an ani-
mal, for instance a mammal (Fig. 3, 4), develops out of an

Fig. 3. — Egg of a mammal (a simple cell).
a. The small kernel speck or nucleolus (the so-
called germ-spot of the egg), h. Kernel or
nucleus (the so-called germ -bladder of the egg).
c. Cell-substance or protoplasm (the so-called
yolk of the egg), d. Cell-capsule or membrane
(membrane of the yolk) of the egg ; called in
mammals, on account of its transparency, Mem-
brana pellucida.

1 90

THE HISTORY OF CREATION.

egg,- this process of development always begins by the
simple egg-cell (Fig. 3) forming an accumulation of cells

Fig. 4. — First commencement of the development of a mammal's egg, tlie
ao-called " cleavage of the egg " (propagation of the egg.cell by repeated
self -division) . A. The egg, by the formation of the first furrow, falls into
two cells. B. These separate by division into four cells. C. The latter
have divided into eight cells. D. By repeated division a globular accumu-
lation of numerous cells has arisen.

(Fig. 4) by continued self-division. The outer covering, or
cell membrane, of the globular egg remains undivided. First,
the cell-kernel of the egg (the so-called germinal vesicle)
divides itself into two kernels, then follows the cell-sub-
stance (the yolk of the egg) (Fig. 4 J.). In like manner,
the two cells, by continued self-division, separate into four
(Fig. 4 B), these into eight (Fig. 4 (7), into sixteen, thirty-
two, etc., and finally there is produced a globular mass of
very numerous little cells (Fig. 4 D). These now, by further
increase and heterogeneous development (division of labour),
gradually build up the compound many-celled organism.
Every one of us, at the commencement of our individual
development, has undergone the very same process as that
represented in Fig. 4. The egg of a mammal — represented in
Fig. 3, and its development in Fig. 4 — might as well be that
of a man, as of an ape, dog, horse, or any other placental
mammal.

KEPRODUCTION BY FISSION. I91

Now, when one examines this simplest form of propaga-
tion, this self-division, it surely cannot be considered
wonderful that the products of the division of the original
organism should possess the same qualities as the parental
individual. For they are parts or halves of the parental
organism, and the matter or substance in both halves
is the same, and as both the young individuals have
received an equal amount and the same quality of matter
from the parent individual, one can but consider it
natural that the vital phenomena, the physiological qualities
should be the same in both children. In fact, in regard to
their form and substance, as well as to their vital phenomena,
the two produced cells can in no respect be distinguished
from one another, or from the mother cell They have
inherited from her the same nature.

But this same simple propagation by self-division is not
only confined to simple cells — it is the same also in the
higher many-celled organisms; for example, in the coral
zoophytes. Many of them which exhibit a high complexity
of composition and organization, nevertheless, propagate
themselves by simple division. In this case the whole
organism, with all its organs, falls into two equal halves as
soon as by growth it has attained a certain size. Each half
again develops itself, by growth, into a complete individual.
Here, again, it is surely self-evident that the two products
of division will share the qualities of the parental organism,
as they themselves are in fact halves of that parent.

Next to propagation by division we come to propagation
by the formation of buds. This kind of monogony is
exceedingly widely spread. It occurs both in the case of
simple cells (though not frequently) and in the higher organ-

192 THE HISTORY OF CEEATION.

isms composed of many cells. The formation of buds is
universal in the vegetable kingdom, less frequent in the
animal kingdom. However, here also it occurs in the
tribe of Plant-like Animals, especially among the Coral
Zoophytes, and among the greater portion of the Hydroid
Polyps very frequently, further also among some worms
(Planarian Worms, Ring- Worms, Moss Animals, Tuni-
cates). Most branching animal-trees or colonies, which are
exceedingly like branching plants, arise like those plants,
by the formation of buds.

Propagation by the foronation of buds (Gemmatio) is
essentially distinguished from propagation by division, in
the fact that the two organisms thus produced by budding
are not of equal age, and therefore at first are not of equal
value, as they are in the case of division. In division
we cannot clearly distinguish either of the two newly
produced individuals as the parental, that is as the producer,
because, in fact, both have an equal share in the composition
of the original parental individual. If, on the other hand,
an organism sends out a bud, then the latter is the child of
the former. The two individuals are of unequal size and of
unequal form. If, for instance, a cell propagates itself by
the formation of buds, we do not see the ceU fall into two
equal halves, but there appears at one point of it a protube-
rance, which becomes larger and larger, more or less separates
itself from the parental cell, and then grows independently.
In like manner we observe in the budding of a plant or
animal, that a small local growth arises on a part of the
mature individual, which growth becomes larger and larger,
and likewise more or less separates itself from the parental
organism by an independence in its growth. The bud, after

REPRODUCTION BY GERM-BUDS. 1 93

it has attained a certain size, may either completely separate
itself from the parental individual, or it may remain con-
nected with it and form a stock or colony, whilst at the
same time its life may be quite independent of that of its
parent. While the growth which starts the propagation, in
the case of self-division, is a total one affecting the whole
body, it is in the formation of buds only partial, affecting
merely a portion of the parental organism. But here, also,
the bud — the newly-produced individual which remains so
long most directly connected with the parental organism,
and which proceeds from it — retains the essential qualities
and the original tendency of development of its parent.

A third mode of non-sexual propagation, that of the
formation of germ-huds (Polysporogonia), is intimately
connected with the formation of buds. In the case of the
lower, imperfect organisms, among animals, especially in the
case of the Plant-like animals and Worms, we very fre-
quently find that in the interior of an individual composed
of many cells, a small group of cells separates itself from
those surrounding it, and that this small isolated group
gradually developes itself into an individual, which, becomes
like the parent, and sooner or later comes out of it.
Thus, for example, in the body of the Fluke-worms (Tre-
matodes) there often arise numerous little bodies consisting
of many cells, that is germ-buds, or polyspores, which at
an early stage separate themselves completely from the
parent body, and leave it when they have attained a certain
stage of development.

The formation of germ- buds is evidently but little different
from real budding. But, on the other hand, it is connected
with a fourth kind of non-sexual propagation, which almost

194 THE HISTORY OF CliEATIOK

forms a transition to sexual reproduction, namely, the
formation of germ- cells (Monosporogonia), which is often
briefly called formation of spores (sporogonia). In this case
it is no longer a group of cells, but a single cell, which
separates itself from the surrounding cells in the interior of
the producing organism, and which only becomes further
developed after it has come out of its parent. After this
germ-cell, or monospore (or, briefly, spore), has left the
parental individual, it multiplies by division, and thus
forms a many-celled organism, which by growth and
gradual development attains the hereditary qualities of the
parental organism. This occurs very generally among lower
plants (Cryptogama).

Although the formation of germ-cells very much resembles
the formation of germ buds, it evidently and very essentially
differs from the latter, and also from the other forms of non-
sexual propagation which have previously been mentioned,
by the fact that only a very small portion of the producing
organism takes part in the propagation and, accordingly, in
the transmission by inheritance. In the case of self-division,
where the whole organism falls into two halves, in the
formation of buds, where a considerable portion of the whole
body, already more or less developed, separates from the
producing individual, we easily understand that the forms
and vital phenomena should be the same in the producing
and produced organism. It is much more difficult to under-
stand in the formation of germ-buds, and more difficult still
in the formation of germ-cells, how this very small, quite
undeveloped portion of the body, this group of cells, or this
single cell, not only directly takes with it certain parental
qualities into its independent existence, but also after its

SEXUAL REPRODUCTION. 1 95

separation from the parental individual develops into a
many-celled body, and in this repeats the forms and vital
phenomena of the original producing organism. This last
form of monogonic propagation — that of the germ cells, or
spore-formation — leads us directly to a form of propagation
which is the most difficult of all to explain, namely, sexual
propagation.

Sexual or aTnpJiigonic jpropagation (Amphigonia) is the
usual method of propagation among all higher animals and
plants. It is evident that it has only developed, at a very
late period of the earth's history, from non-sexual propaga-
tion, and apparently in the first instance from the method
of propapation by germ-cells. In the earliest periods of the
organic history of the earth, all organisms propagated them-
selves in a non-sexual manner, as numerous lower orofanisms
still do, especially all those which are at the lowest stage of
organization, and which, strictly speaking, can be considered
neither as animals nor as plants, and which therefore, as
primary creatures, or Protista, are best excluded from both
the animal and vegetable kingdoms. In the case of the
higher animals and plants, the increase of individuals, as a
rule, is at present brought about in the majority of cases by
sexual propagation.

In aU the chief forms of non-sexual propagation mentioned
above — in fission, in the formation of buds, germ buds, and
germ cells — the separated cell or group of cells was able by
itself to develop into a new individual, but in the case of
sexual propagation the cell must first be fructified by
another generative substance. The fructifying male sperm
must first mix with the female germ-cell (the egg) before
the latter can develop into a new individual. These two

196 THE HISTORY OF CREATION.

different generative substances, the male sperm and the
female egg, are either produced by one and the same indi-
vidual hermaphrodite (Hermaphroditismus), or by two
different individuals (sexual separation, Gonochorismus)
(Gen. Morph. ii. 58, 59).

The simpler and more ancient form of sexual propagation
is through double-sexed individuals (Hermaphroditismus).
It occurs in the great majority of plants, but only in a
minority of animals, for example, in the garden snails,
leeches, earth-worms, and many other worms. Every single
individual among hermaphrodites produces within itself
materials of both sexes — eggs and sperm. In most of the
higher plants every blossom contains both the male organ
(stamens and anther) and the female organs (style and
germ). Every garden snail produces in one part of its
sexual gland eggs, and in another part sperm. Many her-
maphrodites can fructify themselves ; in others, however,
copulation and reciprocal fructification of both hermaphro-
dites is necessary for causing the development of the eo-o-s.
This latter case is evidently a transition to sexual separa-
tion.

Sexual separation (Gonochorismus,) which characterizes
the more complicated of the two kinds of sexual reproduc-
tion, has evidently been developed from the condition of
hermaphroditism at a late period of the organic history of
the world. It is at present the universal method of propa-
gation of the higher animals, and occurs, on the other hand,
only in the minority of plants (for example, in many aquatic
plants, e.g. Hydrocharis, Vallisneria ; and in trees, e.g.
Willows, Poplars). Every organic individual, as a non-
hermaphrodite (Gonochoristus), produces within itself only

VIEGINAL EEPKODUCTION. 197

one of two generative substances, either the male or the
female. The female individuals, both in animals and plants,
produce eggs or egg-cells. The eggs of plants in the case
of flovrering plants (Phanerogama), are commonly called
" embryo sacs " ; in the case of flowerless plants (Crypto-
gama), 'fruit spores." In animals, the male individual
secretes the fructifying sperm (sperma); in plants, the
corpuscles, which correspond to the sperm. In the Phane-
rogama, these are the pollen grains, or flower-dust ; in the
Cryptogama, a sperm, which, like that of most animals,
consists of floating vibratile cells actively moving in a
fluid — the zoosperms, spermatozoa, or sperm-cells.

The so-called virginal reproduction (Parthenogenesis)
offers an interesting form of transition from sexual repro-
duction to the non-sexual formation of germ-cells (which
most resembles it) ; it has been demonstrated to occur in
many cases among Insects, especially by Siebold's ex-
cellent investigations. In this case germ-cells, which
otherwise appear and are formed exactly like egg-cells,
become capable of developing themselves into new indi-
viduals without requiring the fructifying seed. The most
remarkable and most instructive of the different partheno-
genetic phenomena are furnished by those cases in which
the same germ-cells, according as they are fructified or not,
produce different kinds of individuals. Among our common
honey bees, a male individual (a drone) arises oufc of the
eggs of the queen, if the egg has not been fructified ; a
female (a queen, or working bee), if the egg has been fructi-
fied. It is evident from this, that in reality there exists
no wide chasm between sexual and non-sexual reproduc-
tion, but that both modes of reproduction are directly
10

igS THE HISTORY OF CREATION.

connected. The parthenogenesis of Insects must probably
be regarded as a rela'pae from the sexual mode of propaga-
tion (possessed by the original parents of the insects) to the
earlier condition of non-sexual propagation. (Gen. Morph.
ii. 86). In any case, however, sexual reproduction, both in
plants and animals, which seems such a wonderful process,
has only arisen at a later date out of the more ancient
process of non-sexual reproduction. In both cases heredity
is a necessary part of the phenomenon.

In all the different modes of propagation the essential
point of the process is invariably a detachment of a portion
of the parental organism possessing the capability of leading
an individual, independent existence. We may, therefore, in
all cases expect, d 'priori, that the produced individuals—
which are, in fact, as is commonly said, " the flesh and
blood " of the parents — ^will receive the vital characteristics
and qualities of form which the parental individuals possess.
It is simply a larger or smaller quantity of the parental
material, in fact of its albuminous protoplasm, or cell-
substance, which passes to the produced individual. But
together with the material, its vital properties — that is, the
molecular motions of the plasma — are transmitted, which
then manifest themselves in its form. Inheritance by sexual
breeding loses very much of the mysterious and wonderful
character which it at first sight possesses for the uninitiated,
if we consider the above-mentioned series of the different
modes of propagation, and their connection one with another.
It at first appears exceedingly wonderful that in the sexual
propagation of man, and of all higher animals, the small
Qgg, the minute cell, often invisible to the naked eye, is
able to transfer to the produced organism all the qualities

MATERIAL CAUSES OP HEREDITY. 1 99

of the maternal organism, and, no less mysterious, that at
the same time the essential qualities of the paternal
organism are transferred to the offspring by means of the
male sperm, which fructifies the egg-cell by means of a
viscid substance in which minute thread-like ceUs or zoo-
sperms move about. But as soon as we compare the con-
nected stages of the different kinds of propagation, in whicli
the produced organism separates itself more and more as a
distinct growth from the parental individual, and more or
less early enters upon its independent career; as soon as
we consider, at the same time, that the growth and develop-
ment of every higher organism only depends upon the
increase of the cells composing it — that is, upon their
simple propagation by division — it becomes quite evident
that all these remarkable processes belong to one series.

The life of every organic individual is nothing but a
connected chain of very complicated material phenomena
of motion. These motions must be considered as chano^es
in the position and combination of the molecules, that is,
of the smallest particles of animated matter (of atoms
placed together in the most varied manner). The specific,
definite tendency of these orderly, continuous, and inherent
motions of life depends, in every organism, upon the
chemical mingling of the albuminous generative matter to
which it owes its origin. In man, as in the case of the
higher animals which propagate themselves in a sexual
manner, the individual vital motion commences at the
moment in which the egg-cell is fructified by the spermatic
filaments of the seed, in which process both generative
Hubstances actually mix; and here the tendency of the
vital motion is determined by the specific, or more

200 THE HISTOEY OF CREATION.

accurately, by the individual nature of the sperm as well as
of the egg. There can be no doubt as to the purely
mechanical material nature of this process. But here we
stand full of wonder and astonishment before the infinite
and inconceivable delicacy of this albuminous matter. We
are amazed at the undeniable fact that the simple egg-cell
of the maternal organism, and a single paternal sperm-
tliread, transfer the molecular individual vital motion of
these two individuals to the child so accurately, that after-
wards the minutest bodily and mental peculiarities of both
parents reappear in it.

Here we stand before a mechanical phenomenon of
nature of which Virchow, whose genius founded the
" cellular pathology," says with full justice : " If the
naturalist cared to follow the custom of historians and
preachers, and to clothe phenomena, which are in their way
unique, with the hollow pomp of ponderous and sounding
words, this would be the opportunity for him ; for we have
now approached one of those great mysteries of animal
nature, which encircle the region of animal life as opposed
to all the rest of the world of phenomena. The question
of the formation of cells, the question of the excitation of
a continuous and equable motion, and, finally, the questions
of the independence of the nervous system and of the soul
— these are the great problems on which the human mind
can measure its strength." To comprehend the relation of
the male and female to the egg-cell is almost as much as
to solve all those mysteries. The origin and development
of the egg-cell in the mother's body, the transmission of
the bodily and mental peculiarities of the father to it by
his seed, touch upon all the questions which the human

SEXUAL AND NON-SEXUAL HEREDITY. 20I

mind has ever raised about man's existence. And, we add,
these most important questions are solved, by means of the
Theory of Descent, in a purely mechanical and purely
monistic sense !

There can then be no further doubt that, in the sexual
propagation of man and all higher organisms, inheritance,
which is a purely mechanical process, is directly dependent
upon the material continuity of the producing and pro-
duced organism, just as is the case in the simplest non-
sexual propagation of the lower organisms. However, I
must at once take this opportunity of drawing atten-
tion to an important difference which inheritance presents
in sexual and non-sexual propagation. It is a fact long
since acknowledged, that the individual peculiarities of the
producing organism are much more accurately transmitted
to the produced organism by non-sexual than by sexual
propagation. Gardeners have for a long time made use of
this fact in many ways. When, for instance, a single
individual of a species of tree with stiff, upright branches
accidentally produces down-hanging branches, a gardener,
as a rule, cannot transmit this peculiarity by sexual, but
only by non-sexual propagation. The twigs cut off such a
weeping tree and planted as cuttings or slips, afterwards
produce trees having likewise hanging branches, as, for
example, the weeping willows and beeches. Seedlings, on
the other hand, which have been reared out of the seed of
such a weeping tree, generally have the original stiff and
upright form of branches possessed by their ancestors.
The same may be observed in a very striking manner in
the so-called " copper-coloured trees," that is, varieties of
trees which are characterized by a red or reddish brown

202 THE HISTORY OF CREATION

colour of the leaves. OfF-shoots from such copper-coloured
trees (for example, the copper beech), which have been
propagated by cuttings in a non-sexual manner, show the
peculiar colour and nature of the leaves which distinguished
the parental individual, while others reared from seeds of
such a copper-coloured tree return to the green-coloured
condition of leaf.

This difference in inheritance will seem very natural when
we consider that the material connection between the pro-
ducing and produced individuals is much closer and lasts
much longer in non-sexual than in sexual propagation. The
special tendency of the molecular motion of life can there-
fore ^x itself much longer and more thoroughly in the filial
organism, and be more strictly transmitted by non-sexual
than by sexual propagation. All these phenomena, con-
sidered in connection, clearly prove that the transmission of
bodily and mental peculiarities is a purely material and
mechanical process. By propagation a greater or lesser
quantity of albuminous particles, and together with them the
individual form of motion inherent in these molecules of
protoplasm, are transmitted from the parental organism to
the offspring. As this form of motion remains continuous,
the more delicate peculiarities inherent in the parental
organism must sooner or later reappear in the filial
organism.

CHAPTER IX.

LAWS OF TRANSMISSION BY INHERITANCE.
ADAPTATION AND NUTRITION.

Distinction between Conservative and Progressive Transmission bj Inherit-
ance.— Laws of Conservative Transmission : Transmission of Inherited
Characters. — Uninterrupted or Continuous Transmission. — Interrupted
or Latent Transmission. — Alternation of Generations. — Relapse. —
Degeneracy. — Sexual Transmission. — Secondary Sexual Characters. —
Mixed or Amphigonous Transmission. — Hybrids. — Abridged or Simpli-
fied Transmission. — Laws of Progressive Inheritance : Transmission of
Acquired Characters. — Adapted or Acquired Transmission. — Fixed or
Established Transmission. — Homochronous Transmission (Identity in
Epoch). — nomotopic Transmission (Identity in Part) . — Adaptation and
Mutability. — Connection between Adaptation and Nutrition. — Distinc-
tion between Indirect and Direct Adaptation.

In the last chapter we considered Transmission by Inherit-
ance, one of the two universal vital activities of organisms.
Adaptation and Inheritance, which by their interaction
produce the different species of organisms, and we have
endeavoured to trace this very mysterious vital activity to
a more general physiological function of organisms, namely,
to Propagation. This latter in its turn, like other vital
phenomena of animals and plants, depends on physical and
chemical relations. It is true they appear at times ex-
ceedingly complicated, but can nevertheless in reality be
traced to simple mechanical causes — that is, to the relations

204 THE HISTORY OF CREATION.

of attraction and repulsion in the particles or molecules — in
fact, to the motional phenomena of matter.

Now, before we turn our attention to the second function,
the phenomenon of Adaptation or Mutability, which counter-
acts the Transmission by Inheritance, it seems appropriate
first to cast one more glance at the various manifestations of
Heredity, which we may perhaps even now denominate the
" laivs of transmission by inheritance.^* Unfortunately, up
to the present time very little has been done for this most
important subject, either in zoology or in botany, and almost
all we know of the different laws of inheritance is confined
to the experiences of gardeners and farmers. It is not
therefore to be wondered at, that on the whole these exceed-
ingly interesting and important phenomena have not been
investigated with desirable scientific accuracy, or reduced
to the form of scientific laws. Accordingly, what I shall
relate of the different laws of transmission are only some
preliminary fragments taken out of the infinitely rich store
which lies open to our inquiry.

We may first divide all the difierent phenomena of inherit-
ance into two groups, which we may distinguish as the
transmission of inherited characters, and the transmission of
acquired characters ; and we may call the former the con-
servative transmission, and the latter the progressive trans-
mission by inheritance. This distinction depends upon the
exceedingly important fact that the individuals of every
species of animals and plants can transmit to their de-
scendants, not only those qualities which they themselves
have inherited from their ancestors, but also the peculiar,
individual qualities which they have acquired during their
own life. The latter are transmitted by progressive, the

LAWS OF INHERITANCE. 205

former by conservative inheritance. We have now first to
examine the phenomena of conservative inheritance, that is,
the transmission of such quahties as the organism has
already received from its parents or ancestors. (Gen. Morph.
ii. 180.)

Among the phenomena of conservative inheritance we are
first struck by that which is its most general law, and which
we may term the law of uninterrupted or continuous
transmission. It is so universal among the higher animals
and plants, that the uninitiated might overestimate its action
and consider it as the only normal law of transmission by
inheritance. This law simply consists in the fact that
among most species of animals and plants, every generation
is, on the whole, like the preceding — that the parents are as
like the grandparents as they are like the children. " Like
produces like," as is commonly said, but more accurately
" similar things produce similar things." For, in reality, the
descendants of every organism are never absolutely equal
in all points, but only similar in a greater or less degree.
This law is so generally known, that I need not give any
examples of it.

The law of interrupted or latent transmission by inherit-
ance, which might also be termed alternating transmission,
is in a measure opposed to the preceding law. This im-
portant law appears principally active among many lower
animals and plants, and manifests itself in contrast to the
former in the fact that the offspring are not like their
parents, but very dissimilar, and that only the third or a
later generation becomes similar to the first. The grand-
children are like the grandparents, but quite unlike the
parents. This is a remarkable phenomenon, and, as is well

206 THE HISTORY OF CREATION.

known, occurs also very frequently, though in a less degree,
in human families. Every one of my readers doubtless
knows some members of a family who, in this or that pecu-
liarity, much more resemble the grandfather or grandmother
than the father or mother. Sometimes it lies in bodily
peculiarities, for example, features of face, colour of hair,
size of body — sometimes in mental qualities, for example,
temperament, energy, understanding — which are trans-
mitted in this manner. This fact may be observed in
domestic animals as well as in the case of man. Among
the domestic animals most liable to vary — as the dog,
horse, and ox — breeders very frequently find that the pro-
duct by breeding resembles the grandparents far more than
it does its own parental organism. If we express this
general law and the succession of generations by the letters
of the alphabet, then A = C = E, whilst B=D=F, and
so on.

This very remarkable fact appears in a more striking
way in the lower animals and plants than in the
higher, and especially in the well-known phenomenon of
alternation of generations (metagenesis). Here we very
frequently find — for example, among the Planarian worms,
sea-squirts or Tunicates, Zoophytes, and also among ferns
and mosses — that the organic individual in the first place
produces, by propagation, a form completely difierent
from the parental form, and that only the descendants of
this generation, again, become like the first. This regular
change of generation was discovered by the poet Chamisso,
on his voyage round the world in 1819, among the Salpce,
cylindrical tunicates, transparent like glass, which float on
the surface of the sea. Here the larger generation, the in-

LATENT TRANSMISSION. 207

dividuals of which live isolated and possess an eye of the form
of a horse-shoe, produce in a non-sexual manner (by the
formation of buds) a completely different and smaller gene-
ration. The individuals of this second smaller generation
live united in chains and possess a cone-shaped eye.
Every individual of such a chain produces, in a sexual man-
ner (hermaphrodite) again, a non-sexual solitary form of the
first and larger generation.. Among the Salpse, therefore, it
is always the first, third, and fifth generation, and in like
manner the second, fourth, and sixth generations, that are
entirely like one another. However, it is not always only
•one, but in other cases a number of generations, which are
thus leapt over; so that the first generation resembles the
fourth and seventh, the second resembles the fifth and
eighth, the third resembles the sixth and ninth, and so on.
Three different generations alternate with one another ; for
example, among the neat little sea-hiioys (Doliolum), small
tunicates closely related to the Salp^. In this case it is
A = D =G, further, B == E = H, and C = F = I. Among
the plant-lice (Aphides), each sexual generation is followed
by a succession of from eight to ten or twelve non-sexual
generations, which are like one another, but differ from
the sexual generations. Then, again, a sexual generation
reappears like the one long before vanished.

If we further follow this remarkable law of latent or in-
terrupted inheritance, and take into consideration all the
phenomena appertaining to it, we may comprise under it
also the well-known phenomena of reversion. By the term
" reversion " or " atavism " we understand the remarkable
fact known to all breeders of animals, that occasionally
single and individual animals assume a form which has not

2o8 THE HISTORY OF CKEATION.

existed for many generations, but belongs to a generation
which lias long since disappeared. One of the most remark-
able instances of this kind is the fact that in some horses
there sometimes appear singular dark stripes, similar to
those of the zebra, quagga, and other wild species of
African horses. Domestic horses of the most different races
and of all colours sometimes show such dark stripes ; for ex-
ample, a stripe along the back, a stripe across the shoulders,
and the like. The sudden appearance of these stripes can
only be explained by the supposition that it is the effect of
a latent transmission, a relapse into the ancient original
form, which has long since vanished, and was once common,
to all species of horses ; the original form, undoubtedly, was
originally striped like the zebras, quaggas, etc. In like
manner, certain qualities in other domestic animals some-
times appear quite suddenly, which once marked their
wild ancestors, now long since extinct. In plants, also, such
a relapse can be observed very frequently. All my readers
probably know the wild yellow toad-flax (Linaria vulgaris),
a plant very common in our fields and hedges. Its dragon-
mouthed yellow flower contains two long and two short
stamens. But sometimes there appears a single blossom
(Peloria) which is funnel-shaped, and quite regularly com-
posed of five individual and equal sections, with five corre-
sponding stamens. This Peloria can only be explained as a
relapse into the long since extinct and very ancient common
form of all those plants which, like the toad-flax, possess
dragon-mouthed, two-lipped flowers, with two long and two
short stamens. The original form, like the Peloria, pos-
sessed a regular five-spurred blossom, with five equal
stamens, which only later and by degrees have become

REVERSION TO THE WILD FORM. 209

unequal (compare p. 17). All such relapses are to be
brought under the law of interrupted or latent transmission,
although the number of intervening generations may be
enormous.

When cultivated plants or domestic animals become wild,
when they are withdrawn from the conditions of cultivated
life, they experience changes which appear not only as
adaptations to their new mode of life, but partially also as
relapses into the ancient original form out of which the cul-
tivated forms have been developed. Thus the different
kinds of cabbage, which are exceedingly different in form,
may be led back to the original form, by allowing them to
grow wild. In like manner, dogs, horses, heifers, etc., when
growing wild, often revert more or less to a long extinct
generation. An immensely long succession of generations
may pass away before this power of latent transmission be-
comes extinguished.

A third law of conservative transmission may be called
the law of sexual transmission, according to which each sex
transmits to the descendants of the same sex peculiarities
which are not inherited by the descendants of the other sex.
The so-called secondary sexual characters, which in many
respects are of extraordinary interest, everywhere furnish
numerous examples of this law. Subordinate or secondary
sexual characters are those peculiarities of one of the two
sexes which are not directly connected with the sexual
organs themselves ; such characters, which exclusively belong
to the male sex, are, for example, the antlers of the stag, the
mane of the lion, and the spur of the cock. The human
beard, an ornament commonly denied to the female sex, be-
longs to the same class. Similar characteristics by which

2IO THE HISTORY OF CREATION.

the female sex is alone distinguished are, for example, the
developed breasts, with the lactatory glands of female mam-
mals and the pouch of the female opossum. The bodity
size, also, and complexion, differs in female animals of many
species from that of the male. All these secondary sexual
qualities, like the sexual organs themselves, are transmitted
by the male organism only to the male, not to the female,
and vice versa. Contrary facts are rare exceptions to the
rule.

A fourth law of transmission, which has here to be men-
mentioned, in a certain sense contradicts the last, and limits
it, viz. the law of Tnixed or mutual (amphigonous) trans-
mission. This law tells us that every organic individual
produced in a sexual way receives qualities from both
parents, from the father as well as from the mother. This
fact, that personal qualities of each of the two sexes are
transmitted to both male and female descendants, is very
important. Goethe mentions it of himself, in the beautiful
lines —

" Von Vater hab ich die Statur, des Lebens emstes Fiilireii
Von Miitterchen die Frohnatur und Lust zu fabuliren."

** From my father I have my stature and the serious tenour of my life.
From my mother a joyous nature and a turn for poetizing."

This phenomenon, I suppose, is so well-known to all,
that I need not here enter upon it. It is according to the
different portions of their character which father and
mother transmit to their children, that the individual
differences among brothers and sisters are chiefly determined.

The very important and interesting phenomenon of ky-
hridism also belongs to this law of mixed or amphigonous

INHERITANCE IN HYBRIDS. 211

transmission. It alone, wlien rightly estimated, is quite
sufficient to refute the prevailing dogma of the constancy
of species. Plants, as well as animals, belonging to quite
different species, may sexually mingle with one another
and produce descendants which in many cases can again
propagate themselves, and that indeed either (more fre-
quently) by mingling with one of the two parental species,
or (more rarely) by pure in-breeding, hybrid mixing with
hybrid. The latter is well established, for example, in the
hybrids of hares and rabbits (Lepus Darwinii, p. 147). The
hybrids of a horse and a donkey, two different species of
the same genus (Equus), are well known. These hybrids
differ according as the father or the mother belongs to the
one or the other species — the horse or the donkey. The
mule produced by a mare and a he-donkey has qualities
quite different from those of the jinny (Hinnus), the hybrid
of a horse and she-donkey. In both cases the hybrid pro-
duced by the crossing of two different species is a mixed
form, which receives qualities from both parents ; but the
qualities of the hybrid are different, according to the form
of the crossing. In like manner, mulattoes produced by
a European and a negress show a different mixture of
characters from the hybrids produced by a negro with a
European female. In these phenomena of hybrid-breed-
ing, as well as in the other laws of transmission pre-
viously mentioned, we are as yet unable to show the acting-
causes in detail ; but no naturalist doubts the fact that the
causes are in aU cases purely mechanical and dependent
upon the nature of organic matter itself If we possessed
more delicate means of investigation than our rude organs
of sense and auxilliary instruments, we should be able to

212 THE HISTORY OF CREATION.

discover those causes, and to trace them to the chemical and
physical properties of matter.

Among the phenomena of conservative transmission, we
must now mention, as the fifth law, the law of abridged or
simplifed transmission. This law is very important in
regard to embryology or ontogeny, that is in regard to the
history of the development of organic individuals. Onto-
geny, or the history of the development of individuals, as I
have already mentioned in the first chapter (p. 10), and as I
subsequently shall explain more minutely, is nothing but
a short and quick repetition of Phytogeny dependent on
the laws of transmission and adaptation — that is, a repetition
of the palseontological history of development of the whole
organic tribe, or phylum, to which the organism belongs.
If, for example, we follow the individual development of a
man, an ape, or any other higher mammal within the ma-
ternal body from the egg, we find that the foetus or embryo
arising out of the egg passes through a series of very differ-
ent forms, which on the whole agTees with, or at least runs
parallel to, a series of forms which is presented to us by the
historical chain of ancestors of the higher mammals. Among
these ancestors we may mention certain fishes, amphibians,
marsupials, etc. But the parallelism or agreement of these
two series of development is never quite complete ; on the
contrary, in ontogeny there are always gaps and leaps which
indicate the omission of certain stages belonging to the
phylogeny. Fritz Miiller, in his excellent work, " Fiir
Darwin," ^^ has clearly shown in the case of the Crus-
tacea, or crabs, that " the historical record preserved in the
individual history of development is gradually obscured,
in proportion as development takes a more and move direct

TEANSMISSION OF ACQUIEED CHAKACTERS. 213

route from the egg to the complete animal." This process
of obscuring and shortening is determined by the law of
abridged transmission, and I mention it here specially be-
cause it is of great importance for the understanding of
embryology, and because it explains the fact, at first so
strano^e, that the whole series of forms which our ancestors
have passed through in their gradual development are no
lonocer visible in the series of forms of our own individual
development from the egg.

Opposed to the laws of the conservative transmission,
hitherto discussed, are the phenomena of the transmission of
the second series, that is, the laws of progressive transmis-
sion hy inheritance. As already mentioned, they depend
upon the fact that the organism transmits to its descendants
not only those qualities which it has inherited from its own
ancestors, but also a number of those individual qualities
which it has acquired during its own lifetime. Adaptation
is here seen to be connected with transmission by inherit-
ance (Gen. Morph. ii. 186).

At the head of these important phenomena of progressive
transmission, we may mention the law of adapted or ac-
quired transmission. In reality it asserts nothing more
than what I have said above, that in certain circumstances
the organism is capable of transmitting to its descendants
all the qualities which it has acquired during its own life
by adaptation. This phenomenon, of course, shows itself
most distinctly when the newly acquired peculiarity pro-
duces any considerable change in the inherited form. This
is the case in the examples I mentioned in the preceding
chapter as to transmission in general, in the case of the men
with six fingers and toes, the porcupine men, copper beeches,

214 THE HISTORY OF CREATION.

weeping willows, etc. The transmission of acquired diseases,
such as consumption, madness, and albinism, likewise form
very striking examples. Albinoes are those individuals who
are distinguished by the absence of colouring matter, or
pigments, in the skin. They are of frequent occurrence
among men, animals, and plants. In the case of animals of
a definite dark colour, individuals are not unfrequently born
which are entirely without colour, and in animals possessing
eyes, this absence of pigment extends even to the eyes, so
that the iris of the eye, which is commonly of a bright or
intense colour, is colourless, but appears red, on account of
the blood-vessels being seen through it. Among many
animals, such as rabbits and mice, albinoes v/ith white fur
and red eyes are so much liked that they are propagated in
great numbers as a special race. This would be impossible
were it not for the law of the transmission of adaptations.

Which of the changes acquired by an organism are trans-
mitted to its descendants, and which are not, cannot be
determined a priori, and we are unfortunately not ac-
quainted with the definite conditions under which the
transmission takes place. We only know in a general way
that certain acquired qualities are much more easily trans-
mitted than others, for example, more easily than the
mutilations caused by accidents. These latter are generally
not transmitted by inheritance, otherwise the descendants of
men who have lost their arms or legs would be born without
the corresponding arm or leg; but here, also, exceptions
occur, and a race of dogs without tails has been produced
by consistently cutting off the tails of both sexes of the dog
during several generations. A few years ago a case occurred
on an estate near Jena, in which by a careless slamming of

HORNLESS CATTLE AND OTTER-SHEEP. 21 5

a stable door the tail of a bull was wrenched off, and the
calves begotten by this bull were all born without a tail.
This is certainly an exception ; but it is very important to
note the fact, that under certain unknown conditions such
violent changes are transmitted in the same manner as
many diseases.

In very many cases the change which is transmitted and
preserved by adapted transmission is constitutional or in-
born, as in the case of albinism mentioned before. The
change then depends upon that form of adaptation which
we call the indirect or potential. A very striking instance
is furnished by the hornless cattle of Paraguay, in South
America. A special race of oxen is there bred which is
entirely without horns. It is descended from a single bull,
which was born in 1770 of an ordinary pair of parents, and
the absence of horns was the result of some unknown cause.
All the descendants of this bull produced with a homed cow
were entirely without horns. This quality was found
advantageous, and by propagating the hornless cattle among
one another, a hornless race was obtained, which at present
has almost entirely supplanted the horned cattle in Paraguay.
The case of the otter-sheep of North America forms a similar
example. In the year 1791 a farmer, by name Seth Wright,
lived in Massachusetts, in North America ; in his normally
formed flock of sheep a lamb was suddenly born with a sur-
prisingly long body and very short and crooked legs. It
was therefore unable to take any great leaps, and especially
unable to leap across a hedge into a neighbour's garden
— a quality which seemed advantageous to the owner, as the
territories were divided by hedges. It therefore occurred to
him to transmit this quality to other sheep, and by crossing

2l6 THE HISTORY OF CREATION.

this ram with normally shaped ewes, he produced a whole
race of sheep, all of which had the qualities of the father,
short and crooked legs and a long body. None of them
could leap across the hedges, and they therefore were much
liked and jDropagated in Massachusetts.

A second law, which likewise belongs to the series of
progressive transmissions, may be called the law of estab-
lished or habitual transmission. It manifests itself in this,
that qualities acquired by an organism during its individual
life are the more certainly transmitted to its descendants
the longer the causes of that change have been in action,
and that this change becomes the more certainly the pro-
perty of all subsequent generations the longer the cause of
change acts upon these latter also. The quality newly
acquired by adaptation or mutation must be established
or constituted to a certain degree before we can cal-
culate with any probability that it will be transmitted
at all to the descendants. In this respect transmission re-
sembles adaptation. The longer a newly acquired quality
has been transmitted by inheritance, the more certainly
will it be preserved in future generations. If, therefore,
for example, a gardener by methodical treatment has pro-
duced a new kind of apple, he may calculate with the
greater certainty upon preserving the desired peculiarity
of this sort the longer he has transmitted the same by
inheritance. The same is clearly shown in the trans-
mission of diseases. The longer consumption or madness
has been hereditary in a family the deeper is the root of
the evil, and the more probable ib is that all succeeding
generations will suffer from it.

We may conclude the consideration of the phenomena of

PEEIOD AT WHICH CHAEACTEllS APPEAR. 21 7

inlieritance with the two very important laws of homotopic
and conteviporxineous transmission by inheritance. We
understand by them the fact that changes acquired by an
organism during its life, and transmitted to its descendants,
appear in the same part of the body in which the parental
organism was first affected by them, and that they also
appear in the offspring at the same age as that at which
they did so in the parent.

The law of contemporaneous or homochronous transmis-
sion, which Darwin calls the law of " transmission in
corresponding periods of life," can be shown very clearly
in the transmission of diseases, especially of such as are
recognized as very destructive, on account of their here-
ditary character. They generally appear in the organism
of the child at the time corresponding with that in which
the parental organism contracted the disease. Hereditary
diseases of the lungs, liver, teeth, brain, skin, etc., usually
appear in the descendants at the same period, or a little
earlier than they showed themselves in the parental organ-
ism, or were contracted by it. The calf gets its horns at
the same period of life as its parents did. In like manner
the young stag receives its antlers at the same period of life
in which they appeared in its father or grandfather. In
every one of the different sorts of vine the grapes ripen at
the same time as they did in the case of their progenitors.
It is well known that the time of ripening varies greatly in
the different sorts : but as all are descended from a sinGrle
species, this variation has been acquired by the progenitors
of the several sorts, and has then been transmitted by
inheritance.

The laiu of homotopic transmission, which is most

2l8 THE HISTORY OF CREATION.

closely connected with the last mentioned law, and which
might be called the law of transmission in corresponding
parts of the body, may also be very distinctly recognized in
pathological cases of inheritance. Large moles, for example,
or accumulations of pigment in several parts of the skin,
tumours also, often appear during many generations, not only
at the same period of life, but also in the same part of the
skin. Excessive development of fat in certain parts of the
body is likewise transmitted by inheritance. Above all, it
is to be noted that numerous examples of this, as well as of
the preceding law, may be found everywhere in the study of
embryology. Both the la%u of ho'tnochronous and homotopic
transmission are fundamental laws of emhryologi/, or
ontogeny. For these laws explain the remarkable fact that
the different successive forms of individual development in
all generations of one and the same species always appear
in the same order of succession, and that the variations of the
body always take place in the same parts. This apparently
simple and self-evident phenomenon is nevertheless exceed-
ingly wonderful and cuiious; we cannot explain its real
causes, but may confidently assert that they are due to the
direct transmission of the organic matter from the parental
organism to that of the ofispring, as we have seen above in
the case of the process of transmission in general, by a con-
sideration of the details of the various modes of reproduction.
Having thus, then, considered the most important laws of
Inheritance, we now turn to the second series of phenomena
bearing on natural selection, viz. to those of Adaptation or
Variation, These phenomena, taken as a whole, stand in a
certain opposition to the phenomena of Inheritance, and the
difficulty which arises in examining them consists mainly

INTERACTION OF HEREDITY AND ADAPTATION. 219

in the two sets of phenomena being so completely inter-
crossed and interwoven. We are but seldom able to say
with certainty — of the variations of form which occur before
our eyes — how much is owing to Inheritance, and how much
to Adaptation. All characters of form, by which organisms
are distinguished, are caused either by Inheritance or by
Adaptation ; but as both functions are continually inter-
acting with each other, it is extremely difficult for the
systematic inquirer to recognize the share belonging to each
of the two functions in the special structure of individual
forms. This is, at present, all the more difficult, because we
are as yet scarcely aware of the immense importance of this
fact, and because most naturalists have neglected the theory
of Adaptation, as well as that of Inheritance. The laws of
Inheritance, which we have just discussed, as well as the
laws of Adaptation, which we shall consider directly, in
reality form only a small portion of the phenomena existing
in this domain, but which have not as yet been investi-
gated ; and since every one of these laws can interact with
every other, it is clear that there is an infinite complication
of physiological actions, which are at work in the con-
struction of organisms.

But now, as to the phenomenon of variation or adaptation
in general, we must, as in the case of inheritance, view it as
a quite universal, physiological fundamental quality of all
organisms, without exception — as a manifestation of life
which cannot be separated from the idea of organism.
Strictly speaking, we must here also, as in the case of in-
heritance, distinguish between Adaptation itself and Adapta-
bility. By Adaptation (Adaptio), or Variation ( Variatio), we
understand the fact that the organism, in consequence of

2 20 THE HISTORY OF CREATION.

influences of the surrounding outer world, assumes certain
new peculiarities in its vital activity, composition, and form
which it has not inherited from its parents ; these acquired
individual qualities are opposed to those which have been
inherited, or, in other words, those which have been trans-
mitted to it from its parents or ancestors. On the other
hand, we call Adaptability (Adaptabilitas), or Variability
(VariabiHtas), the capability inherent in all organisms to
acquire such new qualities under the influence of the outer
world. (Gen. Morph. ii. 191.)

The Tindeniable fact of organic adaptation or variation is
universally known, and can be observed at every moment in
thousands of phenomena surrounding us. But just because
the phenomena of variation by external influences appear so
self-evident, they have hitherto undergone scarcely any
accurate scientific investigation. To them belong all the
phenomena which we look upon as the results of contracting
and giving up habits, of practice and giving up practices, or
as the results of training, of education, of acclimatization, of
gymnastics, etc. Many permanent variations brought about
by causes producing disease, that is to say, many diseases,
are nothing but dangerous adaptations of the organism to
injurious conditions of life. In the case of cultivated plants
and domestic animals, variation is so striking and powerful
that the breeder of animals and the gardener found their
whole mode of proceeding upon it, or rather upon the inter-
action between these phenomena and those of Inheritance.
It is also well known to every one that animals and plants,
in their wild state, are subject to variation. Every syste-
matic treatise on a group of animals or plants, if it were to
be quite complete and exhaustive, ought to mention in every

ADAPTATION EXPLAINED BY NUTRITION. 221

individual species the number of variations which differ
more or less from the prevailing or typical form of the
species. Indeed, in every careful systematic special treatise
one finds, in the case of most species, mention of a number of
such variations, which are described sometimes as individual
deviations, and sometimes as so-called races, varieties, de-
generate species, or subordinate species, and which often
differ exceedingly from the original species, solely in con-
sequence of the adaptation of the organism to the external
conditions of life.

If we now endeavour to fathom the general causes of these
phenomena of Adaptation, we arrive at the conclusion that
in reality they are as simple as the causes of the phenomena
of Inheritance. We have shown that the nature of the
process of propagation furnishes the real explanation of
the facts of Transmission by Inheritance, that is, the trans-
mission of parental matter to the body of the offspring;
and in like manner we can show that the physiological
function of nutrition, or change of substance, affords a
general explanation of Adaptation or Variation. When I
here point to "nutrition" as the fundamental cause of
variation and adaptation, I take this word in its widest sense,
and I understand by it the whole of the material changes
which the organism undergoes in all its parts through the
influences of the surrounding outer world. Nutrition thus
comprises not only the reception of actual nutritive sub-
stances and the influence of different kinds of food, but
also, for example, the action upon the organism of water
and of the atmosphere, the influence of sunlight, of tem-
perature, and of all those meteorological phenomena which

are implied in the term "climate." The indirect and
11

222 THE HISTORY OF CREATION,

direct influence of the nature of the soil and of the
dwelling-place also belong to it ; and further, the extremely
important and varied influence which is exercised upon
every animal and every plant by the surrounding organ-
isms, friends and neighbours, enemies and robbers, para-
sites, etc. All these and many other very important
influences, all of which more or less modify the organism in
its material composition, mnst be taken into consideration
in studying the change of substance wliich goes on in living
things. Adaptation, accordingly, is the consequence of all
those material variations which are produced in the change
of substance of the organism by the external conditions of
existence, or by the influences of the surrounding external
world.

How very much every organism is dependent upon the
whole of its external surroundings, and changed by their
alteration, is, in a general way, well known to every one.
Only think how much the human power of action is de-
pendent upon the temperature of the air, or how much the
disposition of our minds depends upon the colour of the sky.
Accordingly as the sky is cloudless and sunny, or covered
with large heavy clouds, our state of mind is cheerful or dull.
How diflerently do we feel and think in a forest during a
stormy winter night and during a bright summer day !
All the different moods of our soul depend upon purely
material changes of our brain, upon movements of molecular
plasma, which are started through the medium of the senses
by the different influences of light, warmth, moisture, etc.
" We are a plaything to every pressure of the air." No less
important and deeply influential are the effects produced
upon our mind and body by the different quality and

NUTRITION EXPLAINS ADAPTATION. 223

quantity of food. Our mental activity, the activity of our
understanding and of our imagination, is quite different
accordingly as we have taken tea or coffee, wine or beer,
before or during our work. Our moods, wishes, and feelings
are quite different when we are hungry and when we are
satisfied. The national character of Englishmen and
Gauchos, in South America, who live principally on meat
and food rich in nitrogen, is wholly different from that of
the Irish, feeding on potatoes, and that of the Chinese, living
on rice, both of whom take food deficient in nitrogen. The
latter also form much more fat than the former. Here, as
everjnvhere, the variations of the mind go hand in hand
with the corresponding transformations of the body ; both
are produced by purely material causes. But all other
organisms, in the same way as man, are varied and changed
by the different influences of nutrition. It is well known
that we can change in an arbitrary way the form, size,
colour, etc., of our cultivated plants and domestic animals,
by change of food; that, for example, we can take from,
or give to a plant definite qualities, accordingly as we
expose it to a greater or less degree of sunlight and moisture.
As these phenomena are generally widely known, and as we
shall proceed presently to the consideration of the different
laws of adaptation, we will not dwell here any longer on
the general facts of variation.

As the different laws of transmission may be naturaUy
divided into the two series of conservative and progressive
transmission, so we may also distinguish between two series
of the laws of adaptation, first, the series of laws of indirect,
and secondly, the series of laws of direct adaptation. The
latter may also be called the laws of actual, and the former
the laws of potential, adaptation.

2 24 THE HISTORY OF CREATION.

The first series, comprising the phenomena of indirect
(potential) adaptation, has, on the whole, hitherto been
little attended to, and Darwin has the merit of having
directed special attention to this series of changes. It is some-
what difficult to place this subject clearly before the reader ;
I will endeavour to rhake it clear hereafter by examples.
Speaking quite generally, indirect or potential adaptation
consists in the fact that certain changes in the organism,
effected by the influence of nutrition (in its widest sense) and
of the external conditions of existence in general, show them-
selves not in the individual form of the respective organism,
but in that of its descendants. Thus, especially in organisms
propagating themselves in a sexual way, the reproductive
sj^stem, or sexual apparatus, is often influenced by external
causes (which little aflect the rest of the organism), to such a
degree that its descendants show a complete alteration of
form. This can be seen very strikingly in artificially pro-
duced monstrosities. Monstrosities can be produced by sub-
jecting the parental organism to certain extraordinary con-
ditions of life, and, curiously enough, such an extraordinary
condition of life does not produce a change of the organ-
ism itself, but a change in its descendants. This cannot be
called transmission by inheritance, because it is not a quality
existing in the parental organism that is transmitted by
inheritance. It is, on the contrary, a change aflfecting the
parental organism, but not perceptible in it, that appears in
the peculiar formation of its descendants. It is only the
impulse to this new formation which is transmitted in pro-
pagation through the egg of the mother or the sperm of
the father. The new formation exists in the parental
organism only as a possibility (potential) ; in the descend-
ants it becomes a reality (actual).

DIRECT AND INDIRECT ADAPTATION. 225

As this very important and very general phenomenon had
hitherto been entirely neglected, people were inclined to
consider all the visible variations and transformations of
organic forms as phenomena of adaptation of the second
series, that is, as phenomena of direct or actual adaptation.
The essence of this latter kind of adaptation consists in the
fact that the change affecting the organism (through nutri-
tion, etc.) shows itself immediately by some transformation,
and does not only make itself apparent in the descend-
ants. To this class belong all the well-known phenomena
in which we can directly trace the transforming influence of
climate, food, education, training, etc., in their effects upon
the individual itself.

We have seen how the two series of phenomena of pro-
gressive and conservative transmission, in spite of their
difference in principle, in many ways interfere with and
modify each other, and in many ways co-operate with and
cross each other. The same is the case, in a still higher
degree, in the two series of phenomena of indirect and
direct adaptation, which are opposed to each other and yet
closely connected. Some naturalists, especially Darwin and
Carl Vogt, ascribe to the indirect or potential adaptation
by far the more important and almost exclusive influence.
But the majority of naturalists have hitherto been inclined
to take the opposite view, and to attribute the principal
influence to direct or actual adaptation. I consider this
controversy, in the mean while, as almost useless. It is but
seldom that we are in a condition, in any individual case of
variation, to judge how much of it belongs to direct and
how much to indirect adaptation. We are, on the whole,
still too little acquainted with these exceedingly important

226

THE HISTORY OF CREATION.

and intricate relations, and can only assert, in a general
way, that the transformation of organic forms is to be
ascribed either to direct adaptation alone, or to indirect
adaptation alone, or lastly, to the co-operation of both direct
and indirect adaptation.

CHAPTER X.

LAWS OF ADAPTATION.

Laws of Indirect or Potential Adaptation, — Individual Adaptation. —
Monstrous or Sudden Adaptation. — Sexual Adaptation. — Laws of Direct
or Actual Adaptation. — Universal Adaptation. — Cumulative Adaptation.
— Cumulative Influence of External Conditions of Existence and
Cumulative Counter-Influence of the Organism. — Free Will. — Use and
Non-use of Organs. — Practice and Habit. — Correlative Adaptation. —
Correlation of Development. — Correlation of Organs. — Explanation of
Indirect or Potential Adaptation by the Correlation of the Sexual
Organs and of the other parts of the Body. — Divergent Adaptation. —
Unlimited or Infinite Adaptation.

In the last chapter we reduced into two groups the phe-
nomena of Adaptation or Variation, which, in connection
and interaction with the phenomena of Heredity, produce
all the endless variety of forms in animals and plants —
first, the group of indirect or potential, and secondly, the
group of direct or actual Adaptation. We shall occupy
ourselves with a closer examination of the different laws
which we can discover in these two groups of the phe-
nomena of variation. Let us first take into consideration
the remarkable and very important, although hitherto
much neglected, phenomena of indirect variation.

Indirect or potential adaptation manifests itself, it will be
remembered, in the striking and exceedingly important fact

228 THE HISTORY OF CREATION.

tliat organic individuals experience transformations and
assume forms in consequence of changes of nutrition which
have not operated on them themselves, but upon their
parental organism. The transforming influence of the
external conditions of existence, of climate, of nutrition,
etc., shows its effects here not directly in the transform-
ation of the organism itself, but indirectly in that of its
descendants. (Gen. Morph. ii. 202.)

As the principal and most universal of the laws of in-
direct variation must be mentioned the law of indi-
vidual adaptation, or the important proposition that all
oro^anic individuals from the commencement of their indi-
vidual existence are unequal, although often very much
alike. As a proof of this proposition, I may at once point
to the fact, tJiat in the human race in general all brothers
and sisters, all children of the same parents, are unequal
from their birth. No one will venture to assert that two
children at their birth are perfectly alike : that the size of
the individual parts of their bodies, the number of hairs on
their heads, the number of cells composing their outer skins
or epidermis, the number of blood-cells are the same in both
children, or that both children have come into the world
with the same abilities or talents. But what more specially
proves this law of individual difference, is the fact that in
the case of those animals which produce several young ones
at a time, — for instance, dogs and cats, — all the young of
each birth differ from one another more or less strikingly
in size and colour of the individual parts of the body, or
in strength, etc. Now this law is universal. All organic
individuals from their beginning are distinguished by cer-
tain, though often extremely minute, differences, and the

MONSTEOSITIES. 229

cause of these individual differences, though in detail usually
utterly unknown to us, depends partly or entirely on certain
influences which the organs of propagation in the parental
organism have undergone.

A second law of indirect adaptation, which we shall
call the law of ^monstrous or sudden adaptation, is of less
importance and less general than the law of individual
adaptation. Here the divergences of the child-organism
from the parental form are so striking that, as a rule, we
may designate them as monstrosities. In many cases they
are produced, as has been proved by experiments, by the
parental organism having been subject to a certain treat-
ment, and placed under peculiar conditions of nutrition ; for
example, when air and light are withdrawn from it, or when
other influences powerfully acting upon its nutrition are
changed in a certain way. The new condition of existcDce
causes a strong and striking modification of form, not
directly of the organism itself, but only of that of its de-
scendants. The mode of this influence in detail we cannot
discover, and we can only in a very general way detect a
causal connection between the abnormal formation of the
child and a certain change in the conditions of existence
of its parents exerting a special influence upon the organs
of propagation in the latter. The previously mentioned
phenomenon of albinism probably belongs to this group of
abnormal or sudden variations, also the individual cases
of human beings with six fingers and toes, the case of
the hornless cattle, as well as those of sheep and goats
with four or six horns. The abnormal deviation in all
these cases probably owes its origin to a cause which
at first only affected the reproductive system of the

230 THE HISTOEY OF CREATION.

parental organism, the egg of the mother or the sperm of
the father.

A third curious manifestation of indirect adaptation may-
be termed the law of sexual adaptation. Under this name
we indicate the remarkable fact that certain influences,
which act upon the male organs of propagation only, affect
the structure of the male descendants, and in like manner
other influences, which act upon the female organs of propa-
gation only, manifest their efiect only in the change of struc-
ture of the female descendants. This remarkable pheno-
menon is still very obscure, ^and has not as yet been
investigated, but is probably of great importance in regard
to the origin of " secondary sexual characteristics," to which
we have already made allusion.

All the phenomena of sexual, monstrous, and individual
adaptation, which we may comprise under the name of the
laws of indirect or ^potential adaptation, are as yet very
little known to us in their real nature and in their deeper
causal connection. Only this much we can at present main-
tain with certainty, that numerous and important trans-
formations in organic forms owe their existence to this
process. Many and striking variations of form solely de-
pend on causes which at first only affect the nutrition of the
parental organism, and specially its organs of propagation.
Evidently the relations in which the sexual organs stand to
other parts of the body are of the gTeatest importance. We
shall have more to say of these presently, when we speak of
the law of correlative adaptation. How powerfully the
variations in the conditions of life and nutrition affect the
propagation of organisms is rendered obvious by the re-
markable fact that numerous wild animals which we keep

DIRECT ADAPTATION, 23 1

in our zoological gardens, and exotic plants which are grown
in our botanical gardens, are no longer able to reproduce
themselves. This is the case, for example, with most birds of
prey, parrots, and monkeys. The elephant, also, and the
animals of prey of the bear genus, in captivity hardly ever
produce young ones. In like manner many plants in a cul-
tivated state become sterile. The two sexes may indeed
unite, but no fructification, or no development of the fructi-
fted germ, takes place. From this it follows with certainty
that the changed mode of nutrition in the cultivated state is
able completely to destroy the capability of reproduction,
and therefore to exercise the greatest influence upon the
sexual organs. In like manner other adaptations or varia-
tions of nutrition in the parental organism may cause, not
indeed a complete want of descendants, but stiU important
changes in their form.

Much better known than the phenomena of indirect or
potential adaptation are those of direct or actual adapta-
tion, to the consideration of which we now turn our at-
tention. To them belong aU those changes of organisms
which are generally considered to be the results of practice,
habit, training, education, etc. ; also those changes of or-
ganic forms which are effected directly by the influence of
nutrition, of climate, and other external conditions of exist-
ence. As has already been remarked in direct or actual
adaptation, the transforming influence of the external cause
affects the form of the organism itself, and does not only
manifest itself in that of the descendants. (Gen. Morph.
ii. 207.)

We may place the law of universal adaptation at the
head of the different laws of direct or actual adaptation,

232 THE HISTOEY OF CT.EATION.

because it is the chief and most comprehensive among them.
It may be briefly explained in the following proposition:
" All organic individuals become unequal to one another in
the course of their life by adaptation to different conditions
of life, although the individuals of one and the same species
remain mostly very much ahke." A certain inequality of
organic individuals, as we have seen, was already to be
assumed in virtue of the law of individual (indirect) adapt-
ation. But, beyond this, the original inequality of indivi-
duals is afterwards increased by the fact that every individual,
during its own independent life, subjects and adapts itself
to its own peculiar conditions of existence. All different
individuals of every species, however like they may be in
their first stages of hfe, become in the further course of
their existence less like to one another. Thev deviate
from one another in more or less important peculiari-
ties, and this is a natural consequence of the different condi-
tions under which the individuals live. There are no two
single individuals of any species which can complete their
life under exactly the same external circumstances. The
vital conditions of nutrition, of moisture, air, light ; further,
the vital conditions of society, the inter-relations with
surrounding individuals of the same or other species, are
different in every individual being ; and this difference
first affects the functions, and later changes the form of
every individual organism. K the children of a human
family show, even at the beginning, certain individual
inequalities which we may consider as the consequence
of individual (indirect) adaptation, they will appear
still more different at a later period of life, when each
child has passed through different experiences, and has

DIRECT ADAPTATION. 233

adapted itself to different conditions of life. The original
difference of the individual processes of development, evi-
dently becomes greater the longer the life lasts and the
more various the external conditions which influence the
separate individuals. This may be demonstrated in the
simplest manner in man, as well as in domestic animals and
cultivated plants, in which the vital conditions may be ar-
bitrarily modified. Two brothers, of whom one is brought
up as a workman and the other as a priest, develop quite
differently in body as well as in mind ; in like manner, two
dogs of one and the same birth, of which one is trained as a
sporting dog and the other chained up as a watch dog. The
same observation may also readily be made as to organic in-
dividuals in a natural state. If, for instance, one carefully
compares all the trees in a fir or beech forest, which con-
sists of trees of a single species, one finds that among
all the hundreds or thousands of trees, there are not two
individual trees completely agreeing in size of trunk and
other parts, in the number of branches, leaves, etc. Every-
where we find individual inequalities which, in part at
least, are merely the consequences of the different conditions
of life under which the trees have developed. It is true we
can never say with certainty how much of this dissimilarity
in aU the individuals of every species may have originally
been caused by indirect individual adaptation, and how
much of it acquired under the influence of direct or uni-
versal adaptation.

A second series of phenomena of direct adaptation, which
we may comprise under the law of cumulative adaptoMon,
is no less important and general than universal adaptation.
Under this name I include a great number of very important

234 THE HrsTony of creation.

plienomei^, which are usually divided into two quite
distinct groups. Naturalists, as a rule, have distinguished,
first, those variations of organisms which are produced
directly by the permanent influence of external conditions
(by the constant action of nutrition, of climate, of surround-
ings, etc.), and secondly, those variations which arise from
habit and practice, from accustoming themselves to definite
conditions of life, and from the use and non-use of organs.
The latter influences have been set forth especially by
Lamarck as important causes of the change of organic
forms, while the former have for a very long time been
recognized as such more generally.

The sharp distinction usually made between these two
groups of cumulative adaptation, and which even Darwin
stiU maintains, disappears as soon as we reflect more
accurately and deeply upon the real nature and causal
foundation of these two, apparently very different, series
of adaptations. We then arrive at the conviction that in
both cases there are always two different active causes to
be dealt with : on the one hand the external influence or
action of adaptative conditions of life, and on the other
hand the internal reaction of the organism which subjects
and adapts itself to that condition of life. If cumulative
adaptation is considered from the first point of view alone,
and the transforming actions of the permanent external con-
ditions of life are traced to those conditions solely, then the
principal stress is laid unduly upon the external factor, and
the necessary internal reaction of the organism is not taken
into proper consideration. If, on the other hand, cumulative
adaptation is mijustly regarded solely in relation to its
second factor, and the transforming action of the organism

DIRECT ADAPTATION. 235

itself, its reaction against the external influences, its change
by practice, habit, use, or non-use of organs, is put into the
foreground, then we forget that this reaction is first called
into play by the action of external conditions of existence.
Hence it seems that the distinction made between these two
groups lies only in the difl*erent manner of viewing them,
and I believe that they can, with full justice, be considered
as one. The most essential fact in these phenomena of
cumulative adaptation is that the change of the organism
which manifests itself first in the functions, and at a later
period in the form, is the result either of long enduring, or
of often repeated, influences of an external cause. The
smallest cause, by cumulation of its action, can attain the
greatest results.

There are innumerable examples of this kind of direct
adaptation. In whatever direction we may examine the
life of animals and plants, we discover on all hands
evident and undeniable changes of this kind. Let me first
mention some of those phenomena of adaptation occasioned
directly by nutrition itself. Every one knows that the
domestic animals which are bred for certain purposes can
be variously modified, according to the different quantity
and quality of the food given to them. If a farmer in
breeding sheep wishes to produce fine wool, he gives them
different food from what he would give if he wished to obtain
good flesh or an abundance of fat. Choice race and
carriage horses receive better food than dray and cart
horses. Even the bodily form of man — for example, the
amount of fat — is quite different according to his nutrition.
Food containing much nitrogen produces little fat, that
containing little nitrogen produces a great deal' of fat.

2;^6 THE HISTOHY OF CREATION.

People who, by means of Banting's system, at present so
popular, wish to become thin eat only meat and eggs — no
bread, no potatoes. The important variations that can be
produced among cultivated plants, solely by changing the
quantity and quality of nourishment, are well known. The
same plant acquires an altogether different appearance,
according as it is placed in a dry and warm place, exposed
to the sunlight or placed in a cool damp spot in the shade.
Many plants, if transferred to the sea shore, get in a short
space of time thick, fleshy leaves, and the same plants
placed in a particularly dry and hot locality get thin hairy
leaves. All these variations arise directly from the cumu-
lative influence of changed nutrition.

But it is not only the quantity and quality of the articles
of nutrition which aflect and powerfully change and trans-
form the organism, but it is affected also by all the other
external conditions of existence, above all by its nearest
organic surroundings, the society of friendly or hostile
organisms. One and the same kind of tree develops itself
quite differently in an open locality, where it is free on
all sides, and in a forest where it must adapt itself to its
surroundings, where it is pressed on all sides by its
nearest neighbours, and is forced to shoot upwards. In
the former case, the branches of the tree spread widely out ;
in the latter, the trunk extends upwards, and the top of
the tree remains small and contracted. How powerfully
all these circumstances, and how powerfully the hostile or
friendly influence of surrounding organisms, of parasites,
etc., affect every animal and every plant, is so well known,
that it appears superfluous to quote further examples. The
change of form, or transformation which is thereby effected,

THE FEEEDOM OF THE WILL. 237

is never solely tlie direct result of the external influence,
but must always be traced to the corresponding reaction,
and to the activity of the organism itself, which consists in
contracting a habit, or practice, and in the use or non-use of
organs. The fact that these latter phenomena, as a rule,
have been considered distinct from the former, is owing first
to the one-sided manner of viewing them already mentioned,
and secondly to the wrong notion which has been formed
as to the nature and the influence of the activity of the
will in animals.

The activity of the will, which is the organ of habit, of
practice, of the use or non-use of organs among animals, is,
like every other activity of the animal soul, dependent upon
material processes in the central nervous system, upon
peculiar motions which emanate from the albuminous
matter of the ganglion cells, and the nervous fibres con-
nected with them. The will, as well as the other mental
activities, in higher animals, in this respect is different from
that of men only in quantity, not in quality. The will of
the animal, as well as that of man, is never free. The
widely spread dogma of the freedom of the will is, from a
scientific point of view, altogether untenable. Every
physiologist who scientifically investigates the activity of
the will in man and animals, must of necessity arrive at the
conviction that in reality the will is never free, but is
always determined by external or internal infiuences. These
influences are for the most part ideas which have been
either formed by Adaptation or by Inheritance, and are
traceable to one or other of these two physiological functions.
As soon as we strictly examine the action of our own will,
without the traditional prejudice about its freedom, we

238 THE HISTORY OF CREATION.

perceive that every apparently free action of the will is
the result of previous ideas, which are based on notions
inherited or otherwise acquired, and are therefore, in the
end, dependent on the laws of Adaptation and Inheritance.
The same also applies to the action of the will in all animals.
As soon as their will is considered in connection with their
mode of life, in its relation to the changes which the mode
of life is subject to from external conditions, we are at once
convinced that no other view is possible. Hence the changes
of the will which follow the changes of nutrition, and
which, in the form of practice, habit, etc., produce variations
in structure, must be reckoned among the other material
processes of cumulative adaptation.

Whilst an animal's will is adapting itself to changed
conditions of existence by the acquisition of new habits,
practices, etc., it not unfrequently effects the most remark-
able transformations of the organic form. Numerous
instances of this may be found everywhere in animal life.
Thus, for example, many organs in domestic animals are
suppressed, when in consequence of a changed mode of life
they cease to act. Ducks and fowls in a wild state fly
exceedingly well, but lose this facility more or less in a
cultivated state. They accustom themselves to use their
legs more than their wings, and in consequence the muscles
and skeleton used in flying are essentially changed in their
development and form. Darwin has proved this by a very
careful comparative measurement and weighing of the
respective parts of the skeleton in the different races of
domestic ducks, which are all descended from the wild duck
{Anas hoschas). The bones of the wings in tame ducks are
weaker, the bones of the legs, on the other hand, are more

DISUSE OF ORGANS. 239

strongly developed than in wild ducks. In ostriches and
other running birds which have become completely unac-
customed to fly, the consequence is that their wings are
entirely crippled and degenerate into mere "rudimentary
organs " (p. 12). In many domestic animals, especially in
many races of dogs and rabbits, we find that in the
cultivated state they have acquired pendulous ears. This
is simply a consequence of a diminished use of the auri-
cular muscles. In a wild state these animals have to exert
their ears very much in order to discover an approaching
foe, and this is accompanied by a strong development of
the muscular apparatus, which keeps the outer ears in an
upright position, and by which they can turn them in all
directions. In a domestic state the same animals no longer
require to listen so attentively, they prick up or turn their
ears only a little ; the auricular muscles cease to be used,
gradually become weakened, and the ears hang down
flabbily, or become rudimentary.

As in these cases the function, and consequently the form
also, of the organ becomes degenerated through disuse, so,
on the other hand, it becomes more developed by greater
use. This is particularly striking if we compare the brain,
and the mental activity belonging to it, in wild animals
and those domestic animals which are descended from
them. The dog and horse, which are so vastly improved
by cultivation, show an extraordinary degree of mental
development, in comparison with their wild original
ancestors, and evidently the change in the bulk of the
brain, which is connected with it, is mainly determined by
persistent exercise. It is also well known how quickly
and powerfully muscles grow and change their form by con-

240 THE HISTOHY OF CREATION.

tinual practice. Compare, for example, the arms and legs
of a trained gymnast with those of an immovable book-
worm.

How powerfully external influences affect the habits of
animals and their mode of life, and in this way still further
change their forms, is very strikingly shown in many cases
among amphibious animals and reptiles. Our commonest
indigenous snake, the ringed snake, lays eggs which require
three weeks' time to develop. But when it is kept in
captivity, and no sand is strewn in the cage, it does not lay
its eggs, but retains them until the young ones are developed.
The difference between animals producing living offspring
and those laying eggs is here effaced simply by the change
of the ground upon which the animal lives.

The water-salamanders, or tritons, which have been
artificially made to retain their original gills, are extremely
interesting in this respect. The tritons are amphibious
animals, nearly akin to frogs, and possess, like the latter,
in their youth external organs of respiration — ^gills — with
which they, while living in water, breathe the air dissolved
in the water. At a later date a metamorphosis takes place
in tritons, as in frogs. They leave the water, lose their gills,
and accustom themselves to breathe with their lungs. But
if they are prevented from doing this by being kept shut up
in a tank, they do not lose their gills. The gills remain, and
the water salamander continues through life in that low
stage of development, beyond which its lower relations, the
gilled salamanders, or Sozobranchiata, never pass. The gilled
salamander attains its full size, its sexual development, and
reproduces itself without losing its gills.

Great interest was caused a short time ago, among

THE GILLS OF SALAMANDERS. 24 1

zoologists, by the axolotel (Siredon pisciformis), a gilled
salamander from Mexico, nearly related to the triton ; it
had already been known for a long time, and been bred on a
large scale in the zoological garden in Paris. This animal
possesses external gills, like the young salamander, but
retains them all its life, like all other Sozobranchiata. This
gilled salamander generally remains in the water, with its
aquatic organs of respiration, and also propagates itself
there. But in the Paris garden, unexpectedly from among
hundreds of these animals, a small number crept out of
the water on to the dry land, lost their gills, and changed
themselves into gill-less salamanders, which are not to be
distinguished from a North-American genus of tritons
(Amblystoma), and breathe only through lungs. In this
exceedingly curious case we can directly follow the great
stride from water-breathing to air-breathing animals, a
stride which can indeed be observed every spring in the
individual history of development of frogs and salamanders.
Just as every separate frog and every separate salamander
transforms itself from an amphibious animal breathing
through gills, at a later period into one breathing through
lungs, so the whole group of frogs and salamanders have
arisen from animals breathing through gills, and akin to the
Siredon, The Sozobranchiata have remained up to the
present day in that low stage of development. Ontogeny
here explains phylogeny ; the history of the development
of individuals explains that of the whole group (p. 10).

To the law of accumulative adaptation there closely fol-
lows a third law of direct or actual adaptation, the law of
correlative adaptation. According to this important law,
actual adaptation not only changes those parts of the

242 THE HISTORY OF CREATION.

organism which are directly affected by its influence, but
other parts also not directly affected by it. This is the
consequence of organic solidarity, and especially of the
unity of the nutrition existing among all the parts of
every organism. If, for example, the hairiness of the leaves
increases in a plant by its being transferred to a dry locality,
then this change reacts upon the nutrition of other parts,
and it ma}^ result in a shortening of the parts of the stalk,
and produce a more contracted form of the whole plant.
In some races of pigs and dogs — for example, in the
Turkish dog — which by adaptation to a warmer climate have
more or less lost their hair, the teeth also have degenerated.
Whales and Endentata (armadillos), which by their curious
skin-coverino: are removed from the other mammals, also
show the greatest deviations in the formation of their teeth.
Further, those races of domestic animals (oxen and pigs)
which have acquired short legs have, as a rule, also a short
and compact head. Among other examples, the races of
pigeons which have the longest legs are also characterized by
the lonofest beaks. The same correlation between the lenofth
of the legs and beaks is universal in the order of stilted-birds
(Grallatores), in storks, cranes, snipe, etc. The correlations
which thus exist between different parts of the organism
are most remarkable, but their real cause is unknown to us.
In general, we can of course say, the changes of nutrition
affecting an individual part must necessarily react on the
other parts, because the nutrition of every organism is a
connected, centralized activity. But why just this or that
part should exhibit this or that particular correlation is in
most cases quite unknown to us. We know a great number
of such correlations in nutrition ; they are especially seen in

CORRELATION OF ORGANS. 243

those changes of animals and plants which give rise to an.
absence of pigment (noticed previously) — in albinoes. The
want of the usual colouring matter goes hand in hand with
certain changes in the formation of other parts ; for example,
of the muscular and osseous system, consequently of organic
systems which are not at all ultimately connected with
the system of the outer skin. Very frequently albinoes are
more feebly developed, and consequently the whole structure
of the body is more delicate and weak than in coloured
animals of the same species. The organs of the senses and
nervous system are in like manner curiously affected when
there is this want of pigment. White cats with blue eyes
are nearly always deaf White horses are distinguished
from coloured horses by their special liability to form sarko-
matous tumours. In man, also, the degree of the development
of pigment in the outer skin greatly influences the suscepti-
bility of the organism for certain diseases ; so that, for
instance, Europeans with a dark complexion, black hair,
and brown eyes become more easily acclimatized to tropical
countries, and are less subject to the diseases there prevalent
(inflammation of the liver, yellow fever, etc.) than Europeans
of white complexion, fair hair, and blue eyes. (Compare
above, p. 150.)

Among these correlations in the formation of difl*erent
organs, those are specially remarkable which exist between
the sexual organs and other parts of the body. No change
of any part reacts so powerfully upon the other parts of the
body as a certain treatment of the sexual organs. Farmers
who wish to obtain an abundant formation of fat in pigs
sheep, etc., remove the sexual organs by cutting them out
(castration), and this is indeed done to animals of both sexes,

244 THE HISTORY OP CREATION.

The result is an excessive development of fat. The same is
done to the singers in certain religious corporations. These
unfortunates are castrated in early youth, in order that they
may retain their high boyish voices. In consequence of this
mutilation of the genitals, the larynx remains in its youth-
ful stage of development. The muscular tissues of the body
remain at the same time weakly developed, while below the
skin an abundance of fat accumulates. But this mutilation
also powerfully reacts upon the development of the nervous
system, the energy of the will, etc., and it is well known that
human castrates, or eunuchs, as well as castrated animals, are
utterly deficient in the special psychical character which
distinguishes the male sex. Man is a man, both in body
and soul, solely through his male generative glands.

These most important and influential correlations between
the sexual organs and the other parts of the body, especially
the brain, are found equally in both sexes. This might be
expected even a priori, because in most animals the two
kinds of organs develop themselves from the same foun-
dation, and at the beginning are not different. In man, as
in the rest of the vertebrate animals, the male and female
organs in the original state of the germ are entirely the
same, and the differences of the two sexes only gradually
arise in the course of embryonic development (in man, in the
ninth week of embryonic life), by one and the same gland
developing in the female as the ovary, and in the male as
the testicle. Every change of the female ovary, therefore,
has a no less important reaction upon the whole female
organism than every change of the testicle has upon the male
organism. Virchow has expressed the importance of this
correlation in his admirable essay on " Das Weib und die

CORRELATIONS OF THE SEXUAL GLANDS. 245

Zelle ** (" Woman and tlie Cell "), in tlie following words : —
" Woman is woman only by her sexual glands ; all the
peculiarities of her body and mind, of her nutrition and her
nervous activity, the sweet delicacy and roundness of her
limbs, the peculiar formation of the pelvis, the develop-
ment of the breasts, the continuance of the high voice, that
beautiful ornament of hair on her head, with the scarcely
perceptible soft down on the rest of the skin — then again,
the depth of feeling, the truth of her direct perceptions, her
gentleness, devotion, and fidelity — in short, all the feminine
qualities which we admire and honour in a true woman are
but a dependence of the ovary. Take this ovary away, and
the man- woman stands before us — a loathly abortion."

The same close correlation between the sexual organs and
the other parts of the body occurs among plants as generally
as among animals. If one wishes to obtain an abundance of
fruit from a garden plant, the growth of the leaves is cur-
tailed by cutting off some of them. If, on the other hand,
an ornamental plant with a luxuriance of large and beautiful
leaves is desired, then the development of the blossoms and
fruit is prevented by cutting off the flower buds. In both
cases one system of organs develops at the cost of the others.
Thus, also, most variations in the formation of leaves in
wild plants result in corresponding transformations of the
generative parts or blossoms. The great importance of this
' compensation of development," of this " correlation of
parts," has been already set forth by Goethe, by Geoffroy St.
Hilaire, and other nature-philosophers. It rests mainly
upon the fact that direct or actual adaptation cannot pro-
duce an important change in a single part of the body,

without at the same time affecting the whole organism.
12

246 THE HISTORY OF CREATION.

The correlative adaptation between the reproductive organs
and the other parts of the body deserves a very special con-
sideration, because it is, above all others, likely to throw
light upon the obscure and mysterious phenomena of in-
direct or potential adaptation, which have already been
considered. For just as every change of the sexual organs
powerfully reacts upon the rest of the body, so on the other
hand every important change in another part of the body
must necessarily more or less react on the sexual organs.
This reaction, however, will only become perceptible in the
formation of the offspring which arise out of the changed
.generative parts. It is, in fact, precisely those remarkable
and imperceptible changes of the genital system (in them-
selves utterly insignificant changes) — changes of the eggs
and the sperm — brought about by such correlations, which
have the greatest influence upon the formation of the ofi"-
spring, and all the phenomena of indirect or potential adapt-
ation previously mentioned may in the end be traced to
correlative adaptation.

A further series of remarkable examples of correlative
adaptation is furnished by the different animals and plants
which become degenerated through parasitic life or para-
sitism. No other change in the mode of life so much
affects the shapes of organisms as the adoption of a
parasitical life. Plants thereby lose their green leaves ; as,
for instance, our native parasitical plants, Orobanche, La-
thrsea, Monotropa. Animals which originally have lived
freely and independently, but afterwards adopt a parasitical
mode of life on other animals or plants, in the first place
cease to use their organs of motion and their organs of
sense. The loss of this activity is succeeded by the loss of

DIVISION OF LABOUR. 247

the organs themselves, and thus we find, for example, many
crabs, or Crustacea, which in their youth possess a tolerably
high degree of organization, viz. legs, antennse, and eyes, in
old age completely degenerate, living as parasites, with-
out eyes, without apparatus of motion, and without antennae.
The lively, active form of youth, has become a shapeless,
motionless lump. Only the most necessary organs of nutri-
tion and propagation retain their activity; aU the rest of
the body has degenerated. Evidently these complete trans-
formations are, to a large extent, the direct consequences of
cumulative adaption, of the non-use and defective exercise
of the organs, but a great portion of them must certainly
be attributed also to correlative adaptation. (Compare Plate
X. and XI.).

A seventh law of adaptation, the fourth in the group of
direct adaptation, is the law of divergent adaptation. By
this law we indicate the fact that parts originally formed
alike have developed in different ways under the influence
of external conditions. This law of adaptation is extremely
important for the explanation of the phenomenon of
division of labour, or polymorphism. "We can see this
very easily in our own selves ; for instance, in the activity
of our two hands. We usually accustom our right hand
to quite diiSerent work from that which we give our left,
and in consequence of the different occupation there arises
a different formation of the two hands. The right hand,
which we use much more than the left, shows a stronger
development of the nerves, muscles, and bones. The same
applies to the whole arm. In most human beings the
bones and flesh of the right arm are, in consequence
of their being more employed, stronger and heavier than

248 THE HISTORY OF CEEATION.

those of the left arm. Now, as the special use of the right
arm has been adopted and transmitted by inheritance for
thousands of years among Europeans, the stronger shape
and size of the right arm have already become hereditary.
P. Harting, an excellent Dutch naturalist, has shown by
measuring and weighing newly-born children, that even in
them the right arm is more developed than the left.

According to the same law of divergent adaptation, both
eyes also frequently develop differently. If, for example, a
naturalist accustoms himself always to use one eye for the
microscope (it is better to use the left), then that eye will
acquire a power different from that of the other, and this
division of labour is of great advantage. The one eye will
become more short-sighted, and better suited for seeing
things near at hand ; the other eye becomes, on the contrary,
more long-sighted, more acute for looking at an object in the
distance. If, on the other hand, the naturalist alternately uses
both eyes for the microscope, he will not acquire the short-
sightedness of the one eye and the compensatory degree of
long-sight in the other, which is attained by a wise distribu-
tion of these different functions of sight between the two
eyes. Here then again the function, that is the activity, of
originally equally-formed organs can become divergent by
habit ; the function reacts again upon the form of the organ,
and thus we find, after a long duration of such an influence,
a change in the more delicate parts and the relative growth
of the divergent organs, which in the end becomes apparent
even in their coarser outlines.

Divergent adaptation can very easily be perceived among
plants, especially in creepers. Branches of one and the
same creeping plant, which originally were formed alike,

I

ADAPTATION IS UNLIMITED. 249

acquire a completely different form and extent, a completely
different degree of curvature and diameter of spiral winding,
according as they twine themselves round a thinner or a
thicker bar. The divergent change of form of parts origin-
ally identical in form, which tending in different directions
develop themselves under different external conditions, can
be distinctly demonstrated in many other examples. As
this divergent adaptation interacts with progressive inherit-
ance, it becomes the cause of a division of labour among the
different organs.

An eighth and last law of adaptation we may call the
law of unlimited or infinite adaptation. By it we simply
mean to express that we know of no limit to the variation
of organic forms occasioned by the external conditions of
existence. We can assert of no single part of an organism,
that it is no longer variable, or that if it were subjected to
new external conditions it would not be changed by them.
It has never yet been proved by experience that there is a
limit to variation. If, for example, an organ degenerates
from non-use, this degeneration ends finally in a complete
disappearance of the organ, as is the case with the eyes of
many animals. On the other hand, we are able, by continual
practice, habit, and the ever-increasing use of an organ, to
bring it to a degree of perfection which we should at
the beginning have considered to be impossible. If we com-
pare the uncivilized savages with civilized nations, we find
among the former a development of the organs of sense —
sight, smell, and hearing — such as civilized nations can
hardly conceive of On the other hand, the brain, that is
mental activity, among more civilized nations is developed
to a degree of which the wild savages have no idea.

250 THE HISTOilY OF CREATION.

There appears indeed to be a limit given to the adapt-
ability of every organism, by the " type " of its tribe or
phylum ; that is, by the essential fundamental qualities
of this tribe, which have been inherited from a common
ancestor, and transmitted by conservative inheritance to all
its descendants. Thus, for example, no vertebrate animal
can acquire the ventral nerve-chord of articulate animals,
instead of the characteristic spinal marrow of the vertebrate
animals. However, within this hereditary primary form,
within this inalienable type, the degree of adaptability is
unlimited. The elasticity and fluidity of the organic
form manifests itself, within the type, freely in all directions,
and to an unlimited extent. But there are some animals,
as, for example, the parasitically degenerate crabs and
worms, which seem to pass even the limit of type, and
have forfeited all the essential characteristics of their tribe
by an astonishing degree of degeneration. As to the
adaptability of man, it is, as in all other animals, also un-
limited, and since it is manifested in him above all other
animals, in the modifications of the brain, there can be
absolutely no limit to the knowledge which man in a
further progress of mental cultivation may not be able to
exceed The human mind, according to the law of unlimited
adaptation, enjoys an infinite perspective of becoming ever
more and more perfect.

These remarks are sufiicient to show the extent of the
phenomena of Adaptation, and the gTeat importance to
be attached to them. The laws of Adaptation, or the
facts of Variation caused by the influence of external con-
ditions, are just as important as the laws of Inheritance.
All phenomena of Adaptation, in the end, can be traced to

MECHANICAL CAUSES. 25 I

conditions of nutrition of the organism, in the same way
as the phenomena of Inheritance are referable to conditions
of reproduction ; but the latter, as well as the former,
may further be traced to chemical and physical, that is to
mechanical, causes. According to Darwin's Theory of
Selection the new forms of organisms, the transformations
which artificial selection produces in the state of cultivation,
and which natural selection produces in the state of nature,
arise solely by the interaction of such causea

CHAPTER XL

NATURAL SELECTION BY THE STRUGGLE FOR EXIST-
ENCE. DIVISION OF LABOUR AND PROGRESS.

[uteraction of the Two Organic Formative Causes, Inheritance and Adapta-
tion.— Natural and Artificial Selection. — Struggle for Existence, or
Competition for the Necessaries of Life. — Disproportion between the
Number of Possible or Potential, and the Number of Keal or Actual
Individuals. — Complicated Correlations of all Neighbouring Organisms.
— Mode of Action in Natural Selection, — Homochromic Selection as the
Cause of Sjnnpathetic Colourings. — Sexual Selection as the Cause.of the
Secondary Sexual Characters. — Law of Separation or Division of
Labour (Polymorphism, Differentiation, Divergence of Characters). —
Transition of Varieties into Species. — Idea of Species. — Hybridism. —
Law of Progress or Perfectioning (Progressus, Teleosis).

In order to arrive at a right understanding of Darwinism,
it is, above all, necessary that the t^YO organic functions
of Inheritance and Adaptation, which we spoke of in
our last chapter, should be more closely examined. If we
do not, on the one hand, examine the purely mechanical
nature of these two physiological activities, and the various
action of their different laws, and if, on the other hand, we
do not consider how complicated the interaction of these
different laws of Inheritance and Adaptation must be, we
shall not be able to understand how these two functions, by
themselves, have been able to produce all the variety of

ADAPTATION VERSUS INHERITANCE. 253

animal and vegetable forms, which, in fact, they have. We
have, at least, hitherto been unable to discover any other
formative causes besides these two, and if we rightly under-
stand the necessary and infinitely complicated interaction
of Inheritance and Adaptation, we do not require to look
for other unknown causes for the change of organic forms.
These two fundamental causes are, as far as we can see,
completely sufficient.

Even long before Darwin had published his Theory of
Selection, some naturalists, and especially Goethe, had as-
sumed the interaction of two distinct formative tendencies
— a conservative or preserving, and a progressive or chang-
ing formative tendency — as the causes of the variety of
organic forms. The former was called by Goethe the cen-
tripetal or specifying tendency, the latter the centrifugal
tendency, or the tendency to metamorphosis (p. 89). These
two tendencies completely correspond with the two processes
of Inheritance and Adaptation. Inheritance is the centri-
petal or internal formative tendency which strives to keep
the organic form in its species, to form the descendants like
the parents, and always to produce identical things from
generation to generation. Adaptation^ on the other hand,
which counteracts inheritance, is the centrifugal or external
formative tendency, which constantly strives to change the
organic forms through the influence of the vaiying agencies
of the outer world, to create new forms out of those existing,
and entirely to destroy the constancy or permanency of
species. Accordingly as Inheritance or Adaptation pre-
dominates in the struggle, the specific form either remains
constant or changes into a new species. The degree of con-
stancy of form in the different species of animals and

2 54 THE HISTORY OF CREATION.

I'lants, which obtains at any moment, is simply the
necessary result of the momentary predominance which
either of these two formative powers (or physiological
activities) has acquired over the other.

If we now return to the consideration of the process of
selection or choice, the outlines of which we have already
examined, we shall be in a position to see clearly and dis-
tinctly that both artificial and natural selection rest solely
upon the interaction of these two formative tendencies. If
we carefully watch the proceedings of an artificial selector —
a farmer or a gardener — we find that only these two con-
structive forces are used by him for the production of new
forms. The whole art of artificial selection rests solely upon
a thoughtful and wise application of the laws of Inheritance
and Adaptation, and upon their being applied and regulated
in an artistic and systematic manner. Here the will of man
constitutes the selecting force.

The case of natural selection is quite similar, for it also
employs merely these two organic constructive forces, these
ingrained physiological properties of Adaptation and Here-
dity, in order to produce the different species. But the
selecting principle or force, which in artificial selection is
represented by the conscious will of Tnan acting for a definite
purpose, consists in natural selection of the imconscious
struggle for existence acting without a definite plan. What
we mean by '' struggle for existence " has already been ex-
plained in the seventh chapter. It is the recognition of
this exceedingly important identity which constitutes one
of the gi^eatest of Darwin's merits. But as this relation is
very frequently imperfectly or falsely understood, it is
necessary to examine it now more closely, and to illustrate

NUMBER OF ORGANISMS CONSTANT. 255

by a few examples the operation of the struggle for life, and
the operation of natural selection by means of the struggle
for life (Gen. Morph. ii. 231).

When considering the struggle for life, we started from
the fact that the number of germs which all animals and
plants produce is infinitely greater than the number of
individuals which actually come to life and remain alive
for a longer or shorter time. Most organisms produce
during life thousands or millions of germs, from each of
which, under favourable circumstances, a new individual
might arise. In most animals and plants these germs are
eggs, that is cells, which for their development require
sexual fructification. But among the Protista, the lowest
organisms, which are neither animals nor plants, and which
propagate themselves only in a non-sexual manner, the germ-
cells, or spores, require no fructification. Now, in all cases
the number of unsexual, as well as of sexual germs, is out
of all proportion to the number of actually living indi-
viduals of every species.

Taken as a whole, the number of living animals and plants
on our earth remains always about the same. The number
of places in the economy of nature is limited, and in most
parts of the earth's surface these places are always approxi-
mately occupied. Certainly there occur everywhere and in
every year fluctuations in the absolute and in the relative
number of individuals of all species. However, taken as a
whole, these fluctuations are of little importance, and it is
broadly the fact that the total number of all individuals
remains, on an average, almost constant. There is a
constant fluctuation, which depends on the fact that in one
year or another one or other series of animals and plants

256 THE HISTORY OF CREATION.

predominates, and that every year the struggle for life some-
what alters their relations.

Every single species of animals and plants would have
densely peopled the whole earth's surface in a short time, if
it had not had to struggle against a number of enemies and
hostile influences. Even Linnaeus calculated that if an
annual plant only produced two seeds (and there is not one
which produces so few), it would have yielded in twenty
years a million of individuals. Darwin has calculated of
elephants, which of all animals seem the slowest to increase,
that in seven hundred and fifty years the descendants of a
single pair would amount to nineteen millions of indi-
viduals ; this is supposing that every elephant, during its
period of fertility (from the 30th to the 90th year), pro-
duced only three pairs of young ones, and survived itself
to its hundredth year. In like manner the increase
of the number of human beino-s — if calculated on the
average proportion of births to population, and no hin-
drances to the natural increase stood in the way — would be
such as to double the total in twenty-five years. In every
century the total number of men would have increased six-
teen-fold ; whereas we know that the total number of
human beings increases but slowly, and that the increase of
population is very diflferent in different countries. While
European tribes spread over the whole globe, other tribes or
species of men every year draw nearer to their complete
extinction. This is the case especially with the redskins of
America, and v/ith the copper-coloured natives of Australia.
Even if these races were to propagate more abundantly than
the white Europeans, yet they would sooner or later succumb
to the latter in the struggle for life. But of all human

COMPLICATED CONDITIONS. 257

individuals, as of all other organisms, by far the majority
perish at the earliest period of their lives. Of the im-
mense quantity of germs which every species produce, only
very few actually succeed in developing, and of these few
it is again only a very small portion which attain to the age
in which they can reproduce themselves (compare p. 161).

From the disproportion between the immense excess of
organic germs and the small number of chosen individuals
which are actually able to continue in existence beside one
another, there follows of necessity that universal struggle
for life, that constant fight for existence, that perpetual com-
petition for the necessaries of life, of which I gave a
sketch in my seventh chapter. It is this struggle for life
which brings natural selection into play, which in its
turn is made use of by the interaction of the phenomena of
Inheritance and Adaptation as a sifting agency, and which
thus causes a continual change in all organic forms. In
this struggle for acquiring the necessary conditions of
existence, those individuals will always overpower their
rivals who possess any individual privilege, any advan-
tageous quality, of which their fellow competitors are
destitute. It is true we are able only in the fewest
cases (in those animals and plants best known to us) to
form an approximate conception of the infinitely com-
plicated interaction of the numerous circumstances, all
of which here come into combination. Only think how
infinitely varied and complicated are the relations of
every single human being to the rest of mankind, and in
general, to the whole of the surrounding outer world. But
similar relations prevail also among all animals and plants
which live together in one place. All influence one another

258 THE HISTORY OF CREATION.

actively or passively. Every animal and every plant
struggles directly with a number of enemies, beasts of prey,
parasitic animals, etc. Plants standing together struggle
with one another for the space of ground requisite for their
roots, for the necessary amount of light, air, moisture, etc.
In like-manner, animals living together struggle with one
another for their food, dwelling-place, etc. In this most
active and complicated struggle, any personal superiority,
however small, any individual advantage, may possibly
decide the issue in favour of the one possessing it. This
privileged individual remains the victor in the struggle, and
propagates itself, while its fellow-competitors perish before
they succeed in propagating themselves. The personal ad-
vantage which gave it the victory is transmitted by inherit-
ance to its descendants, and by a further development may
become so strongly marked as to cause us to consider the
later generations as a new species.

The infinitely complicated correlations which exist be-
tAveen the organisms of every district, and which must be
looked upon as the real conditions of the struggle for
life, are mostly unknown to us, and are very difficult
to discover. We have hitherto been able to trace them
only to a certain point in individual cases, as in the
example given by Darwin of the relations between cats and
red clover in England. The red clover {Trifolium pratense),
which in England is among the best fodder for cattle,
requires the visit of humming-bees in order to attain the
formation of seeds. These insects, while sucking the honey
from the bottom of the flower, bring the pollen in contact
with the stigma, and thus cause the fructification of the
flower, which never takes place without it. Darwin has

OLD MAIDS AND EOAST BEEF. 259

shown by experiments, that red clover which is not visited
by humming-bees does not yield a single seed. The number
of bees is determined by the number of their enemies, the
most destructive of which are the field-mice. The more the
field-mice predominate, the less the clover is fructified. The
number of field-mice, again, is dependent upon the number
of their enemies, principally cats. Hence in the neighbour-
hood of villages and towns, where many cats are kept, there
are plenty of bees. A great number of cats, therefore, is evi-
dently of gi'eat advantage for the fructification of clover.
This example may be followed stiU. further, as has been done
by Carl Vogt, if we consider that cattle which feed on red
clover are one of the most important foundations of the
wealth of England. Englishmen preserve their bodily and
mental powers chiefly by making excellent meat — roast beef
and beefsteak — their principal food. The English owe the
superiority of their brains and minds over those of other
nations in a great measure to their excellent meat. But this
is clearly indirectly dependent upon the cats, which pursue
the mice. We may, with Huxley, even trace the chain of
causes to those old maids who cherish and keep cats, and,
consequently, are of the greatest importance to the fructifi-
cation of the clover and to the prosperity of England. From
this example we can see that the further it is traced the
wider is the circle of action and of correlation. We can
with certainty maintain that there exist a great number of
such correlations in every plant and in every animal, only
we are not always able to point out and survey their con-
catenation as in the last instance.

Another remarkable example of important correlations is
the following, given by Darwin. In Paraguay, there are

26o THE HISTORY OF CREATION.

no wild oxen and horses, as in the neighbouring parts of
South America, both north and south of Paraguay. This
surprising circumstance is explained simply by the fact that
in that country a kind of small fly is very frequent, and is
in the habit of laying its eggs in the navel of newly-born
calves and foals. The newly-born animals die in conse-
quence of this attack, and the small deadly fly is therefore
the cause of oxen and horses never becoming wild in that
district. Supposing that this fly were destroyed by some
insect-eating bird, then these large mammals would grow
wild in Paraguay, as well as in the neighbouring parts of
South America ; and as they would eat a quantity of certain
species of plants, the whole flora, and, consequently again,
the whole fauna of the country would become changed. It
is hardly necessary to state, that at the same time the whole
economy, and consequently the character, of the human
population would alter.

Thus the prosperity, nay, even the existence of whole
populations can be indirectly determined by a single small
animal or vegetable form in itself extremely insigniflcant.
There are small coral islands whose human inhabitants live
almost entirely upon the fruit of a species of palm. The
fructiflcation of this palm is principally efiected by insects,
which carry the pollen from the male to the female palm
trees. The existence of these useful insects is endangered
by insect-eating birds, which in their turn are pursued by
birds of prey. The birds of prey, however, often succumb
to the attack of a small parasitical mite, which develops itself
in millions in their feathers. This small, dangerous parasite,
again, may be killed by parasitical moulds. Moulds, birds
of prey, and insects would in this case favour the prosperity

HUNGER AND LOVE. 26 1

of the palm, and consequently of man; birds, mites, and
insect-eating birds would, on the other hand, endanger it.

Interesting examples in relation to the change of correla-
tions in the struggle for life are furnished also by those
isolated oceanic islands, uninhabited by man, on which at
different times goats and pigs have been placed by
navigators. These animals become wild, and having no
enemies, they increase in number so excessively, that the
rest of the animal and vegetable population suffer in conse-
quence, and the island finally may become almost a waste,
because there is insufficient food for the large mammals
which increase too numerously. In some cases on an island
thus overrun with goats and pigs, other navigators have let
loose a couple of dogs, who enjoyed this superabundance of
food, and they again increased so numerously, and made
such havoc among the herds, that after several years the dogs
themselves lacked food, and they also almost died out. The
equilibrium of species continually changes in this manner in
nature's economy, accordingly as one or another species
increases at the expense of the rest. In most cases the
relations of different species of animals and plants to one
another are much too complicated for us to be able to follow
them, and I leave it to the reader to picture to himself what
an infinitely complicated machinery is at work in every part
of the world in consequence of this struggle. The impulses
which started the struggle, and which altered and modified
it in different places, are in the end seen to be the impulses
of self-preservation — in fact, the instinct leading individuals
to preserve themselves (the instinct of obtaining food), and
the instinct leading them to preserve the species (instinct of
propagation). It is these two fundamental instincts of

262 THE HISTOEY OF CREATION.

organic self-preservation of which Schiller, the idealist (not
Goethe, the realist ! ) says :

" Meanwliile, until pldlosopliy
Sustains tlie structure of the world.
Her workings will be carried on
By hunger and by love."*

It is these two powerful fundamental instincts which, by
their varying activity, produce such extraordinary differ-
ences in species through the struggle for life. They are
the foundations of the phenomena of Inheritance and
Adaptation. We have, in fact, traced all phenomena of
Inheritance to propagation, all phenomena of Adaptation to
nutrition, as the two wider classes of material phenomena
to which they belong.

The struggle for life in natural selection acts with as
much selective power as does the will of man in artificial
selection. The latter, however, acts according to a plan and
consciously, the former without a plan and unconsciously.
This important difference between artificial and natural
selection deserves especial consideration. For we learn by
it to understand how arrangements serving a purpose
can he produced hy. mechanical causes acting without an
object, as well as hy causes acting for an ohject. The
products of natural selection are arranged even more for a
purpose than the artificial products of man, and yet they
owe their existence not to a creative power acting for a
definite purpose, but to a mechanical relation acting uncon-

♦ " Einstweilen bis den Bau der Welt
Philosophie zusammenhalt,
Erhalt sich ihr Getriebe
Durch Hunger und durch Liebe.

PROTECTIVE COLOURING. 263

sciously and without a plan. If we had not thoroughly
considered the interaction of Inheritance and Adaptation
under the influence of the struggle for life, we should not
at first be inclined to expect such results from this natural
process of selection as are, in fact, furnished by it. It may
therefore be appropriate here to mention a few especially
striking examples of the activity of natural selection.

Let us first take Darwins hoonochromic selection of
animals, or the so-called " sympathetic selection of colours,"
into consideration. Earlier naturalists have remarked that
numerous animals are of nearly the same colour as their
dwelling-place, or the surroundings in which they per-
manently live. Thus, for example, plant-lice and many
other insects living on leaves are of a green colour. The
inhabitants of the deserts, the jerboa, or leaping mice, foxes
of the desert, gazelles, lions, etc., are mostly of a yellow or
yellowish-brown colour, like the sand of the desert. The
polar animals, which live on the ice and snow, are white or
grey, like ice and snow. Many of these animals change their
colour in summer and winter. In summer, when the snow
partly vanishes, the fur of these polar creatures becomes
brownish-grey or blackish, like the naked earth, while in
winter it again becomes white. Butterflies and insects
which hover round the gay and bright flowers are like them
in colour. Now, Darwin explains this surprising circum-
stance quite simply by the fact that such colours as agree
with the colour of the habitation are of the greatest use to
the animals concerned. If these animals are animals of
prey, they will be able to approach the object of their
pursuit more safely and with less likelihood of observation,
and, in like manner, those animals which are pursued will

264 THE HISTORY OF CREATION.

be able to escape more easily, if their colour is as little
different as possible from that of their surroundings. If
therefore originally an animal species varied so as to present
cases of all colours, those individuals whose colour most
resembled the surroundings must have been most favoured
in the struggle for life. They remained more unobserved,
maintained and propagated themselves, while those
individuals or varieties differently coloured died out.

I have tried to explain, by the same sympathetic selection
of colour, the wonderful fact that the majority of pelagic
animals — that is, of those which live on the surface of the
open sea — are bluish, or completely colourless and trans-
parent, hke glass and water itself Such colourless, glassy
animals are met with in the most different classes. To them
belong, among fish, the Helmicthyidse, through whose
crystalline bodies the words of a book can be read ; among
the molluscs, the finned snails (Heteropods) and sea- butter-
flies, or whales-food (Pteropods) ; among worms, the Salpse,
Alciope, and Sagitta ; further, a great number of pelagic
crabs (Crustacea), and the greater part of the Medusae
Umbrella-jellies, (Discomedusae) ; Comb-jellies, (Ctenophora).
All of these pelagic animals, which float on the sui'face of
the ocean, are transparent and colourless, like glass and like
the water itself, while their nearest kin live at the bottom of
the ocean, and are coloured and opaque like the inhabitants
of the land. This remarkable fact, like the sympathetic
colouring of the inhabitants of the earth, can be ex-
plained by natural selection. Among the ancestors of the
pelagic glass-like animals which showed a different degree of
colourlessness and transparency, those that were the most
colourless and transparent must have been most favoured

SEXUAL SELECTION. 265

in the active struggle for life whicli takes place on the
surface of the ocean. They were enabled to approach their
prey the most easily unobserved, and were themselves least
observed by their enemies. Hence they could preserve and
propagate themselves more easily than their more coloured
and opaque relatives; and finally, by accumulative adaptation
and transmission by inheritance, through natural selection,
in the course of many generations their bodies would attain
that degree of crystal-like transparency and colourlessness
which we at present admire in them. (Gen. Morph. ii. 242.)
No less interesting and instructive than homochromic
selection is that species of natural selection which Darwin
calls "sexual selection,'' which explains the origin of the
so-called " secondary sexual characters." We have already
mentioned these subordinate sexual characteristics, so in-
structive in many respects. They comprise those pecu-
liarities of animals and plants which belong only to one
of the two sexes, and which do not stand in any direct
relation to the act of propagation itself (compare above,
p. 244). Such secondary sexual characters occur in great
variety among animals. We all know how striking is the
difference of the two sexes in size and colour in many birds
and butterflies. The male sex is generally the larger and
more beautiful. It often possesses special decorations or
weapons ; as for example, the spur and comb of the cock,
the antlers of the stag and deer, etc. All these peculiarities
of the two sexes have nothing directly to do with pro-
pagation itself, which is effected by the "primary sexual
characters," or actual sexual organs.

Now, the origin of these remarkable " secondary sexual
characters " is explained by Darwin simply by a choice or

266 THE HISTORY OF CREATION,

selection which takes place in the propagation of animals.
In most animals the number of individuals of both sexes is
unequal ; either the number of the female or the number
of the male individuals is greater, and, as a rule, when
the season of propagation approaches, a struggle takes
place between the rivals for the possession of the animals
of the other sex. It is well known with what vigour and
vehemence this struggle is fought out among the higher
animals — among mammals and birds — especially among those
of polygamous habits. Among gallinaceous birds, where for
one cock there are several hens, a severe struggle takes place
between the competing cocks for as large a harem as possible.
The same is the case with many ruminating animals.
Among stags and deer, for instance, at the period of rut,
deadly struggles take place between the males for the
possession of the females. The secondary sexual character
which here distinguishes the males — the antlers of stags
and deer — not possessed by the female, is, according to
Darwin, the consequence of that struggle. Here the motive
and cause determining the struggle is not, as in the case of
the struggle for individual existence, self-preservation, but
the preservation of the species — propagation. There are
numerous passive weapons of defence, as well as active
weapons for attack. The lion's mane, not possessed by the
female, is evidently such a weapon of defence; it is an
excellent means of protection against the bites which the
male lions try to inflict on each other's necks when fighting
for the females ; consequently those males with the strongest
manes have the greatest advantage in the sexual struggle.
The dewlap of the ox and the comb of the cock are similar
defensive weapons. Active weapons of attack, on the other

•4'

SELECTION AND COUKTSHIP. 267

hand, are the antlers of the stag, the tusks of the boar, the
spur of the cock, and the hugely developed pair of jaws in
the male stag-beetle ; all are instruments employed by the
males in the struggle for the females, for annihilating or
chasing away their rivals.

In the cases just mentioned, it is the bodily " struggle to
the death" which determines the origin of the secondary
sexual characters. But, besides these mortal struggles, there
are other important competitions in sexual selection, which
no less influence the structure of the rivals. These consist
principally in the fact that the courting sex tries to please
the other by external finery, by beauty of form, or by a
melodious voice. Darwin thinks that the beautiful voices
of singing birds have principally originated in this way.
Many male birds carry on a regular musical contest when
they contend for the possession of the females. It is known
of several singing birds, that in the breeding season the
males assemble in numbers round the females, and let their
songs resound before them, and that then the females choose
the singers who best please them for their mates. Among
other songsters, individual males pour out their songs in the
loneliness of the forest in order to attract the females, and
the latter follow the most attractive calls. A similar musical
contest, though certainly less melodious, takes place among
crickets and grasshoppers. The male cricket has on its belly
two instruments like drums, and produces with these the
sharp chirping notes which the ancient Greeks curiously
enough thought beautiful music. Male grasshoppers, partly
by using their hind-legs like the bow of a violin against
their wing coverings, and partly by rubbing their wing
coverings together, bring out tones which are, indeed, not

268 THE HISTORY OF CREATION.

melodious to us, but which please the female grasshoppers
so much that they choose the male who fiddles the best.

Among other insects and birds it is not song or, in fact,
any musical accomplishment, but finery or beauty of the
one sex which attracts the other. Thus we find that, amoner
most gallinaceous birds, the cocks are distinguished by combs
on their heads, or by a beautiful tail, which they can spread
out Hke a fan ; as for example, in the case of the peacock
and turkey-cock. The magnificent tail of the bird of para-
dise is also an exclusive ornament of the male sex. In like
manner, among very many other birds and very many
insects, principally among butterflies, the males are dis-
tinguished from the females by special colours or other
decorations. These are evidently the results of sexual
selection. As the females do not possess these attractions
and decorations, we must come to the conclusion that they
have been acquired by degrees by the males in the competi-
tion for the females, which takes its origin in the selective
discrimination of the females.

We may easily picture to ourselves, in detail, the ap-
plication of this interesting conclusion to the human com-
munity. Here, also, the same causes have evidently in-
fluenced the development of the secondary sexual characters.
The characteristics distinguishing the man, as well as those
distinguishing the woman, owe their origin, certainly for the
most part, to the sexual selection of the other sex. In an-
tiquity and in the Middle Ages, especially in the romantic
age of chivalry, it was the bodily struggles to the death — the
tournaments and duels — which determined the choice of the
bride ; the strongest carried home the bride. In more recent
times, however, in our so-called " polished " or " highly civil-

SEXUAL SELECTION IN MAN. 269

ized " society, competing rivals prefer to contend indirectly
by means of musical accomplishments, instrumental per-
formances and song, by bodily cbarms, natural beauty, or
artificial decoration. But by far the most important of these
different forms of sexual selection in man is that form which
is the most exalted, namely, psychical selection, in which the
mental excellencies of the one sex influence and determine
the choice of the other. The most highly intellectually de-
veloped types of men have, throughout generations, when
choosing a partner in life, been guided by her excellencies of
soul, and have thus transmitted these qualities to their pos-
terity, and they have in this way, more than by any other
thing, helped to create the deep chasm which at present
separates civilized men from the rudest savages, and from
our common animal ancestors. In fact, both the part played
by the prevalence of a higher standard of sexual selection,
and the part played by the due division of labour between
the two sexes, is exceedingly important, and I believe that
here we must seek for the most powerful causes which have
determined the origin and the historical development of the
races of man. (Gen. Morph. ii. 247.) As Darwin, in his
exceedingly interesting work, published in 1871, on " The
Origin of Man and Sexual Selection," ^^ has discussed this
subject in the most masterly manner, and has illustrated
it by most remarkable examples, I refer for further detail
to that work.

But now let us look again at two extremely important
organic laws which can be explained by the theory of
selection, as necessary consequences of natural selection
in the struggle for existence. I mean the law of division

of labour, or differentiation, and the law of 'progress, or
13

270 THE HISTORY OF CREATION.

'perfecting. When the phenomena due to these two laws
first became known, through observation of the historical de-
velopment, the individual development, and the comparative
anatomy of animals and plants, naturalists were inclined to
trace them to a direct creative influence. It was supposed to
be part of the plan of the Creator, acting for a definite purpose,
in the course of time to develop the forms of animals and
plants more and more variously, and to bring them more and
more to a state of perfection. We shall evidently make a great
advance in the knowledge of nature if we reject this teleological
and anthropomorphic conception, and if we can prove the two
laws of Division of Labour and Perfecting to be the necessary
consequences of natural selection in the struggle for life.

The first great law which follows directly and of necessity
from natural selection, is that of separation, or differentia-
tion, which is frequently called division of labour, or 'poly-
morjphism, and which Darwin speaks of as divergence of
character. (Gen. Morph. ii. 24^9). We understand by it the
general tendency of all organic individuals to develop them-
selves more and more diversely, and to deviate from the
common primary type. The cause of this general inclination
towards differentiation and the formation of heterogeneous
forms from homogeneous beginnings is, according to Darwin,
simply to be traced to the circumstance that the struggle for
life betw^een every two organisms rages all the more fiercely
the nearer the relation in which they stand to one another,
or the more nearly alike they are. This is an exceedingly
important, and in reality an exceedingly simple relation,
but it is usually not duly considered.

It must be obvious to every one, that in a field of a
certain size, beside the corn-plants which have been sown, a

DIVISION OF LABOUR. 27 1

great number of weeds can exist, and, moreover, in places
which could not have been occupied by corn-plants. The
more dry and sterile places of the ground, in which no corn-
plant would thrive, may still furnish sustenance to weeds of
different kinds ; and such species and individuals of weeds
will more readily be able to exist in such conditions, in pro-
portion as they are suited to adapt themselves to the dif-
ferent parts of the ground. It is the same with animals. It
is evident that a much greater number of animal indivi-
duals can live together in one and the same limited district, if
they are of various and different natures, than if they
are all alike. There are trees (for example, the oak) on
which a couple of hundred of different species of insects live
together. Some feed on the fruits of the tree, others on the
leaves, others again on the bark, the root, etc. It would be
quite impossible for an equal number of individuals to live
on this tree if all were of one species ; if, for example, all fed
on the bark, or only upon the leaves. Exactly the same is
the case in human society. In one and the same small town,
only a certain number of workmen can exist, even when
they follow different occupations. The division of labour,
which is of the greatest use to the whole community, as well
as to the individual workman, is a direct consequence of the
struggle for life, of natural selection ; for this struggle can
be sustained more easily the more the activities, and hence,
also, the forms of the different individuals deviate from
one another. The different function naturally produces its
reaction in changing the form, and the physiological divi-
sion of labour necessarily determines the morphological
differentiation, that is, the " divergence of character." ^^
Now, I beg the reader again to remember that all species

272 THE HISTORY OP CREATION.

of animals and plants are variable, and possess the capability
of adapting themselves to different places or to local rela-
tions. The varieties or races of each species, according to
the laws of adaptation, deviate all the more from the original
primary species, the greater the difference of the new con-
ditions to which they adapt themselves. If we imagine
these varieties — which have proceeded from a common
primary form — to be disposed in the shape of a branching,
radiating bunch, then those varieties will be best able to
exist side by side and propagate which are most distant
from one another, which stand at the ends of the series, or
at the opposite sides of the bunch. Those forms, on the
other hand, occupying a middle position — presenting a state
of transition — have the most difficult position in the struggle
for life. The necessaries of life differ most in the two ex-
tremes, in the varieties most distant from one another, and
consequently these will get into the least serious conflict
with one another in the general struggle for life. But the
intermediate forms, which have deviated less from the
original primary form, require nearly the same neces-
saries of life as the original form, and therefore, in com-
peting for them, they will have to struggle most with, and be
most seriously threatened by, its members. Consequently,
when numerous varieties of a species live side by side on the
same spot of the earth, the extremes, or those forms deviating
most from one another, can much more easily continue to
exist beside one another than the intermediate forms which
have to struggle with each of the different extremes. The
intermediate forms will not be able to resist, for any length
of time, the hostile influences which the extreme forms
victoriously overcome. These alone maintain and propagate

■V.

GOOD AND BAD SPECIES. 273

themselves, and at length cease to be any longer connected
with the original primary species through intermediate forms
of transition. Thus arise " good species " out of varieties.
Thus, then, the struggle for life necessarily favours the
general divergence of organic forms, that is, the constant
tendency of organisms to form new species. This fact does
not rest upon any mystic quality, or upon an unknown forma-
tive tendency, but upon the interaction of Inheritance and
Adaptation m the struggle for life. As the intermediate
forms, that is, the individuals in a state of transition, of
the varieties of every species die out and become extinct,
the process of divergence constantly goes further, and from
the extremes forms develop which we distinguish as new
species.

Although all naturalists have been obliged to acknowledge
the variability and mutability of all species of animals and
plants, yet most of them have hitherto denied that the
modification or transformation of the organic form surpasses
the original limit of the characters of the species. Our
opponents cling to the proposition — " However far a species
may exhibit deviations from its usual form in a collection of
varieties, yet the varieties of it are never so distinct from
one another as two really good species." This assertion,
which Darwin's opponents usually place at the head of
their arg-uments, is utterly untenable and unfounded.
This will become quite clear as soon as we critically
compare the various attempts to define the idea of species.
No naturalist can answer the question as to what is in
reality a " genuine or good species " (" bona species ") ; yet
every systematic naturalist uses this expression every day,
and whole libraries have been written on the question as to

2 74 THE HISTOEY OF CEEATION.

whether this or that observed form is a species or a variety,
whether it is a really good or a bad species. The most
general answer to this question used to be the following :
" To one species belong all those individuals which agree in
all essential characteristics. Essential characteristics of
species are those which remain permanent or constant, and
never become modified or vary." But as soon as a case
occurred in which the characteristic — which had hitherto
le3n considered essential — did become modified, then it was
said, " This characteristic is not essential to the species, for
essential characteristics never vary." Those who argued
thus evidently moved in a circle, and the naivete with
which this circular method of defining species is laid down
in thousands of books as an unassailable truth, and is still
constantly repeated, is truly astonishing.

All other attempts which have been made to arrive at a
definite and logical determination of the idea of organic
■ " species " have, like the last, been utterly futile, and led to
no results. Considering the nature of the case, it cannot be
otherwise. The idea of species is just as truly a relative
one and not absolute, as is the idea of variety, genus family,
order, class, etc. I have proved this in detail in the criti-
cism of the idea of species in my " General Morphology "
(Gen. Morph. ii. 328-364). I will waste no more time on
this unsatisfactory discussion, and now only add a few
words about the relation of species to hyhridism. Formerly
it was regarded as a dogma, that two good species could
never produce hybrids which could reproduce themselves as
such. Those who thus dogmatized almost always appealed
to the hybrids of a horse and donkey, the mule and the
hinny, which, truly enough, are seldom able to reproduce

HYBEIDISM PRODUCES SPECIES. 275

themselves. But the truth is that such unfruitful hybrids
are rare examples, and in the majority of cases hybrids of
two totally different species are fruitful and able to repro-
duce themselves. They can almost always fruitfully mix
with one or other of the parent species, and sometimes
also among themselves ; and in this way completely new
forms can orimnate accordino^ to the laws of " mixed trans-
mission by inheritance."

Thus, in fact, hyhvidisTYi is a source of the origin of oiew
sjpecies, distinct from the source we have hitherto considered
— natural selection. I have already spoken occasionally of
these hybrid species (species hybridse), especially of the
hare-rabbit (Lepus Darwinii), which has arisen from the
crossing of a male hare and a female rabbit ; the goat-
sheep (Capra ovina), which has arisen from the pairing of
a he-goat and ewe; also the different species of thistles
(Cirsium), brambles (Eubus), etc. It is possible that
many wild species have originated in this way, as even
Linnaeus assumed. At all events, these hybrid species,
which can maintain and propagate themselves as weU as
pure species, prove that hybridism cannot serve in any way
to give an absolute definition to the idea of species.

I have already mentioned (p. 47) that the many vain
attempts to define the idea of species theoretically have
nothing whatever to do with the practical distinction of
species. The extensive practical application of the idea of
species, as it is carried out in systematic zoology and botany,
is very instructive as furnishing an example of human folly.
Hitherto, by far the majority of zoologists and botanists, in
distinguishing and describing the different forms of animals
and plants, have endeavoured, above all things, to dis-

276 THE HISTORY OF CREATION.

tinguish accurately kindred forms as so many "good
8])ecies." However, it has been found scarcely possible, in
any group, to make an accurate and consistent distinction
of such "genuine or good species." There are no two
zoologists, no two botanists, who agree in all cases as
to which of the nearly related forms of a genus are good
species, and which are not. All authors have different
views about them. In the genus HieraciuTn, for example,
one of the commonest genera of European plants, no less
than 800 species have been distinguished in Germany alone.
The botanist Fries, however, only admits 106, Koch only 52,
as "good species," and others accept scarcely 20. The
differences in the species of brambles (Rubus) are equally
great. Where one botanist makes more than a hundred
species, a second admits only about one half of that number,
a third only five or six, or even fewer species. The birds of
Germany have long been very accurately known. Bechstein,
in his careful " Natural History of German Birds," has dis-
tinguished 367 species, L. Reichenbach 879, Meyer and Wolff
406, and Brehm, a clergyman learned in ornithology, dis-
tinguishes even more than 900 different species.

Thus we see that here, and, in fact, in every other domain
of systematic zoology and botany, the most arbitrary pro-
ceedings prevail, and, from the nature of the case, must
prevail. For it is quite impossible accurately to distinguish
varieties and races from so-called " good species." Varieties
are commencing species. The variability or adaptability of
species, under the influence of the struggle for life, necessi-
tates the continual and progressive separation or differentia-
tion of varieties, and the perpetual delimitation of new forms.
Whenever these are maintained throughout a number of

THE LAW OF PROGRESS. 277

generations by inheritance, whilst the intermediate forms
die out, they form independent " new species." The origin
of new species by division of labour, or separation, diver-
gence, or differentiation of varieties, is therefore a necessary
consequence of natural selection. ^^

The same kind of interest attaches to a second great law
which we deduce from natural selection, and which is, indeed,
closely connected with the law of Divergence, but in no way
identical with it ; namely, the law of Progress (progressus),
or Perfecting (teleosis). (Gen. Morph. ii. 257). This great
and important law, like the law of differentiation, had
long been empirically established by palseontological ex-
perience, before Darwin's Theory of Selection gave us the
key to the explanation of its cause. The most distinguished
palseontologists have pointed out the law of progress as the
most general result of their investigations of fossil organisms.
This has been specially done by Bronn, whose investiga-
tions on the laws of construction ^^ and the laws of the
development ^^ of organisms, although little heeded, are
excellent, and deserve most careful consideration. The
general results of the law of differentiation and the law of
progress, at which Bronn arrived by a purely mechanical
hypothesis, and by exceedingly accurate, laborious, and care-
ful investigations, are brilliant confirmations of the truth of
these two great laws which we deduce as necessary in-
ferences from the theory of selection.

The law of progress or of perfecting establishes the ex-
ceedingly important fact, on the ground of palseontologi-
cal experience, that in successive periods of this earth's
history, a continual increase in the perfection of organic
formations has taken place. Since that inconceivably

278 THE HISTOEY OF CHEATION.

remote period in which life on our planet began with the
spontaneous generation of Monera, organisms of all groups,
both collectively as well as individually, have continually
become more perfectly and highly developed. The steadily
increasing variety of living forms has always been accom-
panied by progress in organization. The lower the strata
of the earth in which the remains of extinct animals and
plants lie buried, that is, the older the strata are, the more
simple and imperfect are the forms which they contain. This
applies to organisms collectively, as well as to every single
large or small group of them, setting aside, of course, those
exceptions which are due to the process of degeneration,
which we shall discuss hereafter.

As a confirmation of this law I shall mention only the
most important of all animal groups, the tribe of vertebrate
animals. The oldest fossil remains of vertebrate animals
known to us belong to the lowest class, that of Fishes. Upon
these there followed later more perfect Amphibious animals,
then Eeptiles, and lastly, at a much later period, the most
highly organized classes of vertebrate animals. Birds and
Mammals. Of the latter only the lowest and most imperfect
forms, without placenta, appeared at first, such as are the
pouched animals (Marsupials), and afterwards, at a much
later period, the more perfect mammals, with placenta. Of
these, also, at first only the lower kinds appeared, the higher
forms later ; and not until the late tertiary period did man
gradually develop out of these last.

If we follow the historical development of the vegetable
kingdom we shall find the same law operative there. Of
plants there existed at first only the lowest and most im-
perfect classes, the Alg?e or tangles. Later there followed

PEOGEESS, A NECESSARY RESULT. 279

the group of Ferns or FilicinsD (ferns, pole-reeds, scale-
plauts, etc.). But as yet there existed no flowering plants,
or Phanerogama. These originated later with the Gynmo-
sperms (firs and cycads), whose whole structure stands far
below that of the other flowering plants (Angiosperms), and
forms the transition from the group of fern-like plants to the
Angiosperms. These latter developed at a still later date,
and among them there were at first only flowering plants
without corolla (Monocotyledons and Monochlamyds) ; only
later were there flowering plants with a corolla (Dichlamyds).
Finally, again, among these the lower polypetalous plants
preceded the higher gamopetalous plants. The whole series
thus constitutes an irrefutable proof of the great law of pro-
gressive development.

Now, if we ask what is the cause of this fact, we again,
just as in the case of differentiation, come back to natural
selection in the struggle for life. If once more we consider
the whole process of natural selection, how it operates
through the complicated interaction of the different laws
of Inheritance and Adaptation, we shall recognize not
only divergence of character, but also the perfecting of
structure to be the direct and necessary result of it. We
can trace the same thing in the history of the human race.
Here, too, it is natural and necessary that the progressive
division of labour constantly furthers mankind, and urges
every individual branch of human activity into new dis-
coveries and improvements. This progress itself universally
depends on differentiation, and is consequently, like it, a
direct result of natural selection in the struggle for life.

28o THE HISTORY OF CKEATIOK

CHAPTER XIL

LAWS OF DEVELOPMENT OF ORGANIC TPIBES AND OF
INDIVIDUALS. PHYLOGENY AND ONTOGENY.

La^n's of the Development of Mankind : Diflferentiation and Perfecting".
— Meclianical Cause of these two Fundamental Laws. — Progi'ess without
Differentiation, and Differentiation without Progress. — Origin of
Eudimentary Organs by Non-use and Discontinuance of Habit. —
Ontogenesis, or Individual Development of Organisms. — Its General
Importance. — Ontogeny, or the Individual History of Development of
Vertebrate Animals, including Man. — The Fructification of the Egg. —
Formation of the three Germ Layers. — History of the Development of
the Central Nervous System, of the Extremities, of the Branchial
Arches, and of the Tail of Vertebrate Animals. — Causal Connection and
Parallelism of Ontogenesis and Phylogenesis, that is of the Development
of Individuals and Tribes. — Causal Connection of the Parallelism of
Phylogenesis and of Systematic Development. — Parallelism of the three
Organic Series of Development.

If man wishes to understand his position in nature, and
to comprehend as natural facts his relations to the
phenomena of the world cognisable by him, it is abso-
lutely necessary that he should compare human with extra-
human phenomena, and, above all, with animal phenomena.
We have already seen that the exceedingly important
physiological laws of Inheritance and Adaptation apply to
the human organism in the same manner as to the animal
and vegetable kingdoms, and in both cases interact with
one another. Consequently, natural selection in the struggle

PKOGRESS AND DIFFERENTIATION. 28 1

for life acts so as to transform human society, just as
it modifies animals and plants, and in both cases con-
stantly produces new forms. The comparison of the phe-
nomena of human and animal transformation is especially
interesting in connection with the laws of divergence and
progress, the two fundamental laws which, at the end of the
last chapter, we proved to be direct and necessary conse-
quences of natural selection in the struggle for life.

A comparative survey of the history of nations, or what
is called " universal history," will readily yield to us, as the
first and most general result, evidence of a continually in-
creasing variety of human activities, both in the life of in-
dividuals and in that of families and states. This differenti-
ation or separation, this constantly increasing divergence of
human character and the form of human life, is caused by
the ever advancing and more complete division of labour
among individuals. While the most ancient and lowest
stages of human civilization show us throughout the same
rude and simple conditions, we see in every succeeding
period of history, among different nations, a greater variety
of customs, practices, and institutions. The increasing divi-
sion of labour necessitates an increasing variety of forms
corresponding to it. This is expressed even in the for-
mation of the human face. Among the lowest tribes of
nations, most of the individuals resemble one another so
much that European travellers often cannot distinguish
them at all. With increasing civilization the physiognomy
of individuals becomes differentiated, and finally, among the
most highly civilized nations, the English and Germans,
the divergence in the characters of the face is so great that
we very rarely mistake one face for another.

282 THE HISTORY OF CREATION.

The second great fundamental law whicli is obvious in the
history of nations is the great law of progTess or perfecting.
Taken as a whole, the history of man is the history of his
progressive development. It is true that everywhere and at
all times we may notice individual retrogressions, or obsei-ve
that crooked roads towards progress have been taken, which
lead only towards one-sided and external perfecting, and
thus deviate more and more from the higher goal of internal
and enduring perfecting. However, on the whole, the
movement of development of all mankind is and remains a
progressive one, inasmuch as man continually removes him-
self further from his ape-like ancestors, and continually
approaches nearer to his own ideal.

Now, if we wish to know what causes actually determine
these two great laws of development in man, namely, the
law of divergence and the law of progress, we must com-
pare them with the corresponding laws of development in
animals, and on a close examination we shall inevitably come
to the conclusion that the phenomena, as well as their causes,
are exactly the same in the two cases. The course of
development in man, just as in that of animals, being
directed by the two fundamental laws of differentiation
and perfecting, is determined solely by purely mechanical
causes, and is solely the necessary consequence of natural
selection in the struggle for life.

Perhaps in the preceding discussion the question has pre-
sented itself to some — " Are not these two laws identical ?
Is not progress in all cases necessarily connected with diver-
o-ence ? " This question has often been answered in the
affirmative, and Carl Ernst Bar, for example, one of the
greatest investigators in the domain of the history of de-

PROGRESS NOT ALWAYS DIFFERENTIATION. 283

velopment, has set forth the following proposition as one of
the principal laws in the ontogenesis of the animal body : —
" The degree of development (or perfecting) depends on
the stage of separation (or differentiation) of the parts." ^^
Correct as this proposition may be on the whole, yet it is not
universally true. In many individual cases it can be proved
that divergence and progress by no means always coincide.
Every progress is not a differentiation, and every differenti-
ation is not a progress.

Naturalists, guided by purely anatomical considerations,
had already set forth the law relating to progress in organ-
ization, that the perfecting of an organism certainly de-
pends, for the most part, upon the division of labour among
the individual organs and parts of the body, but that there
are also other organic transformations which determine a
progress in organization. One, in particular, which has
been generally recognized, is the numerical diminution of
identical parts. If, for example, we compare the lower
articulated animals of the crustacean group, which possess
numerous pairs of legs, with spiders which never have more
than four pairs of legs, and with insects which always
possess only three pairs of legs, we find this law, for
which a great number of examples could be adduced, con-
firmed. The numerical diminution of pairs of legs is a
progress in the organization of articulated animals. In
like manner the numerical diminution of corresponding
vertebral joints in the trunk of vertebrate animals is a
progress in their organization. Fishes and amphibious
animals with a very large number of identical vertebral
joints are, for this very reason, less perfect and lower than
birds and mammals, in which the vertebral joints, as a

284 THE HISTORY OF CREATION.

whole, are not only very much more differentiated, but in
which the number of corresponding vertebrae is also much
smaller. Further, according to the same law of numerical
diminution, flowers with numerous stamens are more
imperfect than the flowers of kindred plants with a smaller
number of stamens, etc. If therefore originally a great
number of homogeneous parts exist in an organic body, and
if, in the course of very many generations, this number be
gradually decreased, this transformation will be an example
of perfecting.

Another law of progress, which is quite independent of
differentiation, nay, even appears to a certain extent opposed
to it, is the law of centralization. In general the whole
organism is the more perfect the more it is organized as a
unit, the more the parts are subordinate to the whole, and
the more the functions and their organs are centralized. Thus,
for example, the system of blood-vessels is most perfect
where a centralized heart exists. In like manner, the dense
mass of marrow which forms the spinal cord of vertebrate
animals, and the ventral cord of the higher articulated
animals, is more perfect than the decentralized chain of
ganglia of the lower articulated animals, and the scattered
system of ganglia in the molluscs. Considering the difficulty
of explaining these complicated laws of progress in detail, I
cannot here enter upon a closer discussion of them, and
must refer to Bronn's excellent " Morphologischen Studien,"
and to my " General Morphology" (Gen. Morph. i. 370, 550 ;
ii. 257-266).

Just as we have become acquainted with phenomena of
progress, quite independent of divergence, so we shall, on
the other hand, very often meet with divergencies which

EETEOGPvESSIVE DEVELOPMENT. 285

are no perfecting, but which are rather the contrary, that
is retrogressions or degenerations. It is easy to see that the
changes which every species of animal and plant experi-
ences cannot always be improvements. But rather many
i)henomena of differentiation, which are of direct advantao^e
to the organism itself, are yet, in a wider sense, detrimental,
inasmuch as they lessen its general capabilities. Frequently
a relapse to simpler conditions of life takes place, and by
adaptation to them a divergence in a retrograde direction.
If, for instance, organisms which have hitherto lived inde-
pendently accustom themselves to a parasitical life, they
thereby degenerate or retrograde. Such animals, which
hitherto had possessed a well-developed nervous system and
quick organs of sense, as well as the power of moving freely,
lose these when they accustom themselves to a parasitical
mode of life; they consequently retrograde more or less.
There the differentiation viewed by itself is a degeneration,
although it is advantageous to the parasitical organism. In
the struggle for life such an animal, which has accustomed
itself to live at the expense of others, by retaining its eyes
and apparatus of motion, which are of no more use to it,
would only expend so much material uselessly ; and when
it loses these organs, then a great quantity of nourishment
which was employed for the maintenance of these parts,
benefits other parts. In the struggle for life between the
different parasites, therefore, those which make least preten-
sions will have advantage over the others, and this favours
their de2:eneration.

Just as this is found to be the case with the whole
organism, so it is also with the parts of the body of an
iidividual organism. A differentiation of parts, which

286 THE HISTORY OF CREATION.

leads to a partial degeneration, and finally even to the loss
of individual organs, is, when looked at by itself, a degenera-
tion, but yet may be advantageous to the organism in the
struggle for life. It is easier to fight when useless baggage
is thrown aside. Hence we meet everywhere, in the more
highly-developed animal and vegetable bodies, processes of
divergence, the essence of which is that they cause the
degeneration, and finally the loss, of particular parts. And
at this point the most important and instructive of all the
series of phenomena bearing upon the history of organisms
presents itself to us, namely, that of rudhneiitary or
degenerate organs.

It will be remembered that even in my first chapter I
considered this exceedingly remarkable series of phe-
nomena, from a theoretical point of view, as one of the
most important and most striking proofs of the truth
of the doctrine of descent. "We designated as rudimentary
organs those parts of the body which are arranged for a
definite purpose and yet are without function. Let me
remind the reader of the eyes of those animals which
live in the dark in caves and underground, and which con-
sequently never can use them. In these animals we find
real eyes hidden under the skin, frequently developed
exactly as are the eyes of animals which really see;
and yet these eyes never perform any function, indeed
cannot, simply for the reason that they are covered by
an opaque membrane, and consequently no ray of light
falls upon them (compare above, p. 18). In the ancestors
of these animals, which lived in open daylight, the eyes
were well developed, covered by a transparent horny
capsule (cornea), and actually served the purpose of

EUDIMENTARY OUGANS. 287

seeing. But as the animals gradually accustomed them-
selves to an underground mode of life, and withdrew from
the daylight and no longer used their eyes, these became
degenerated.

Very clear examples of rudimentary organs, moreover, are
the wings of animals which cannot fly; for example, the
wings of the running birds, like the ostrich, emeu, casso-
wary, etc., the legs of which have become exceedingly
developed. These birds having lost the habit of flying, have
consequently lost the use of their wings ; however, the
wings are still there, although in a crippled form. We very
frequently find such crippled wings in the class of insects,
most members of which can fly.

From reasons derived from comparative anatomy and
other circumstances, we can with certainty draw the
inference that all insects now living (all dragon-flies, grass-
hoppers, beetles, bees, bugs, flies, butterflies, etc.) have
originated from a single common parental form, from a
primary insect which possessed two well-developed pairs
of wings, and three pairs of legs. Yet there are very many
insects in which either one or both pairs of wings have
become more or less degenerated, and many in which they
have even completely disappeared. For example, in the whole
order of flies, or Diptera, the hinder pair of wings — in the
bee-parasites, or Strepsiptera, on the other hand, the fore pair
of wings — have become degenerated or entirely disappeared.
Moreover, in every order of insects we find individual
genera, or species, in which the wings have more or less
degenerated or disappeared. The latter is the case espe-
cially in parasites. The females have frequently no wings,
whereas the males have ; for instance, in the case of glow-

2SS THE HISTORY OF CREATION.

worms (Lampyris), Strepsiptera, etc. This partial or com-
plete degeneration of the wings of insects has evidently
arisen from natural selection in the struggle for life. For
we find insects without wings living under circumstances
where flying would be useless, or even decidedly injurious
to them. If, for example, insects living on islands fly about
much, it may easily happen that when flying they are blown
into the sea by the wind, and if (as is always the case)
the power of flying is differently developed in different
individuals, then those which fly badly have an advantage
over those which fly well ; they are less easily blown into
the sea, and remain longer in life than the individuals of the
same species which fly well. In the course of many
generations, by the action of natural selection, this cir-
cumstance must necessarily leads to a complete suppression
of the wings. If this conclusion had been arrived at on
purely theoretical grounds, we might be pleased to find its
truth established by facts. For upon isolated islands the
proportion of wingless insects to those possessing wings is
surprisingly large, much larger than among the insects
inhabiting continents. Thus, for example, according to
Wollaston, of the 550 species of beetles which inhabit the
island of Madeira, 220 are wingless, or possess such imperfect
wings that they can no longer fly ; and of the 29 genera
which belong to that island exclusively, no less than 23 con-
tain such species only. It is evident that this remarkable
circumstance does not need to be explained by the special
wisdom of the Creator, but is sufficiently accounted for by
natural selection, because in this case the hereditary disuse
of the wings, the discontinuance of flying in the presence
of dangerous winds, has been very advantageous in the

EUDIMENTARY ORGANS. 289

struggle for life. In other wingless insects the want of
wings has been advantageous for other reasons. Viewed
by itself, the loss of wings is a degeneration, but in these
special conditions of life it is advantageous to the organism
in the struggle for life.

Among other rudimentary organs I may here, by way of
example, further mention the lungs of serpents and serpent-
like lizards. All vertebrate animals possessing lungs, such
as amphibious animals, reptiles, birds, and mammals, have a
pair of lungs, a right and a left one. But in cases where the
body is exceedingly thin and elongated, as in serpents and
serpent-like lizards, there is no room for the one lung by the
side of the other, and it is an evident advantage to the
mechanism of respiration if only one lung is developed. A
single large lung here accomplishes more than two small ones
side by side would do ; and consequently, in these animals, we
invariably find only the right or only the left lung fully
developed. The other is completely aborted, although existing
as a useless rudiment. In like manner, in all birds the right
ovary is aborted and without function ; only the left one is
developed, and yields all the eggs.

I mentioned in the first chapter that man also possesses
such useless and superfluous rudimentary organs, and I
specified as such the muscles which move the ears. Another
of them is the rudiment of the tail which man possesses in
his 3 — 5 tail vertebrae, and which, in the human embryo,
stands out prominently during the first two months of its
development (compare Plates II. and III.). It afterwards
becomes completely hidden. The rudimentary little tail of
man is an irrefutable proof of the fact that he is descended
from tailed ancestors. In woman the tail is generally

290 THE HISTORY OF CREATION.

by one vertebra longer than in man. There still exist
rudimentary muscles in the human tail which formerly
moved it.

Another case of human rudimentary organs, only belong-
ing to the male, and which obtains in like manner in all male
mammals, is furnished by the mammary glands on the
breast, which, as a rule, are active only in the female sex.
However, cases of different mammals are known, especially
of men, sheep, and goats, in which the mammary glands
were fully developed in the male sex, and yielded milk as
food for their offspring. I have already mentioned before
(p. 12) that the rudimentary auricular muscles in man can
still be employed to move their ears, by some persons who
have perseveringly practised them. In fact, rudimentary
organs are frequently very differently developed in different
individuals of the same species ; in some they are tolerably
large, in others very small. This circumstance is very im-
portant for their explanation, as is also the other circum-
stance that generally in embryos, or in a very early period
of life, they are much larger and stronger in proportion to
the rest of the body than they are in fully developed and
fully grown organisms. This can, in particular, be easily
pointed out in the rudimentary sexual organs of plants
(stamens and pistil), which I have already mentioned. They
are proportionately much larger in the young flower-bud
than in the mature flower.

I have remarked (p. 15) that rudimentary or suppressed
organs were the strongest supports of the monistic or
mechanical conception of the universe. If its opponents, the
dualists and teleologists, understood the immense signifi-
cance of rudimentary organs, it would put them into a state

ORIGIN OF NEW ORGANS. 29 1

of despair. Their ludicrous attempts to explain that rudi-
mentary organs were given to organisms by the Creator " for
the sake of symmetry," or " as a formal provision," or " in
consideration of his general plan of creation," sufficiently
prove the utter impotence of their perverse conception of
the universe. I must here repeat that, even if we knew
absolutely nothing of the other phenomena of development,
we should be obliged to believe in the truth of the Theory of
Descent, solely on the ground of the existence of rudimentary
organs. Not one of its opponents has been able to throw
even a feeble glimmer of an acceptable explanation upon
these exceedingly remarkable and important phenomena.
There is scarcely any highly developed animal or vegetable
form which has not some rudimentary organs, and in most
cases it can be shown that they are the products of natural
selection, and that they have become suppressed by disuse.
It is the reverse of the process of formation in which new
organs arise from adaptation to certain conditions of life, and
by the use of parts as yet incompletely developed. It is true
our opponents usually maintain that the origin of altogether
new parts is completely inexplicable by the Theory of
Descent. However, I distinctly assert that to those who
possess a knowledge of comparative anatomy and physiology
this matter does not present the slightest difficulty. Every
one who is familiar with comparative anatomy and the
history of development will find as little difficulty about
the origin of completely new organs as about the utter disap-
pearance of rudimentary organs. The disappearance of the
latter, viewed by itself, is the converse of the origin of the
former. Both processes are particular phenomena of differ-
entiation, which, like all others, can be explained quite

292 THE HISTORY OF CREATION.

simply and meclianically by the action of natural selection
in the struggle for life.

The infinitely important study of rudimentary organs and
their origin, the comparison of their palseontological and
embryological development, now naturally leads us to the
consideration of one of the most important and instructive
of all biological phenomena, namely, the parallelism which
the phenomena of progress and divergence present to us in
three difierent series. When, in the last chapter, we spoke
of perfecting and division of labour, we understood by
those words progress and separation, and those changes
effected by them, which in the long and slow course of the
earth's history have led to a continual variation of the
flora and fauna, to the origin of new and to the disappear-
ance of ancient species of animals and plants. Now,
if we follow the origin, the development, and the life
of every single organic individual, we meet with exactly
the same phenomena of progress and differentiation. The
individual development, or the ontogenesis of every single
organism, from the egg to the complete form is nothing
but a growth attended by a series of diverging and pro-
gressive changes. This applies equally to animals, plants,
and protista. If, for example, we consider the ontogeny
of any mammal, of man, of an ape, or of a pouched
animal, or if we follow the individual development of any
other vertebrate animal of another class, we everywhere
find essentially the same phenomena. Every one of
these animals develops itself originally out of a single cell,
the egg. This cell increases by self-division, and forms a
number of cells, and by the growth of this accumulation of
cells, by the divergent development of originally identical

ONTOGENY OF MAN. 29

-1

cells, by the division of labour among tbem, and by their
perfecting, there arises the perfect organism, the compli-
cated composition of which excites our admiration.

It seems to me here indispensable to draw attention
more closely to those infinitely important and interesting
processes which accompany ontogenesis, or the individual
developvient of organisms, and especially to that of verte-
brate animals, man included. I wish especially to recom-
mend these exceedingly remarkable and instructive phe-
nomena to the reader's most careful consideration, first,
because they are among the strongest supports of the Theory
of Descent, and secondly, because, considering their immense
general importance, they have hitherto been properly con-
sidered only by a few privileged persons.

We cannot indeed but be astonished when we consider
the deep ignorance which still prevails, in the widest circles,
about the facts of the individual development of man and
organisms in general. These facts, the universal importance
of which cannot be estimated too highly, were established,
in their most important outlines, even more than a hundred
years ago, in 1759, by the great German naturalist Caspar
Friedriech Wolfi*, in his classical " Theoria Generationis."
But, just as Lamarck's Theory of Descent, founded in 1809,
lay dormant for half a century, and was only awakened to
new and imperishable life in 1859, by Darwin, in like
manner Wolff"s Theory of Epigenesis remained unknown for
nearly half a century; and it was only after Oken, in 1806,
had published his history of the development of the in-
testinal tube, and after Meckel, in 1812, had translated
Wolffs work (written in Latin) on the same subject into

German, that Wolfi's theory of epigenesis became more gener-
14

294 THE HISTOKY OF CREATION".

ally known, and formed the foundation of all subsequent
investigations of the history of individual development,
The study of ontogenesis now received a great stimulus, and
soon there appeared the classical investigations of the two
friends, Christian Pander (1817) and Carl Ernst Bar (1819).
Bar, in his remarkable " Entwickelungsgeschichte der
Thiere," ^^ worked out the ontogeny of vertebrate ani-
mals in all its important facts. He carried out a series of
such excellent observations, and illustrated them by such
profound philosophical reflections, that his work became
the foundation for a thorough understanding of this im-
portant group of animals, to which, of course, man also
belongs. The facts of embryology alone would be suffi-
cient to solve the question of man's position in nature, which
is the highest of all problems. Look attentively at and
compare the eight figures which are represented on the ad-
joining Plates II. and III., and it will be seen that the
philosophical importance of embryology cannot be too
liighly estimated.

We may well ask, What do our so-called " educated "
circles, wdio think so much of the high civilization of the
19th century, know of these most important biological facts,
of these indispensable foundations for understanding their
own organism ? How much do our speculative philosophers
and theologians know about them, who fancy they can arrive
at an understanding of the human organism by mere guess-
work or divine inspiration ? What indeed do the majority of
naturalists, not excepting the majority of the so-called "zool-
ogists " (including the entomologists !), know about them ?

The answer to this question tells much to the shame of
the persons above indicated, and we must confess, willingly

'~ . .,„ „ 1,

SIMTLAMTY OF MANS AND DOGS EMBRYO. 295

or •anwillingly, that tliese invaluable facts of human ontogeny
are, even at the present day, utterly unknown to most
people, or are in no way valued as they deserve to be. It is
in the face of such a condition of things as this that we see
clearly upon what a wrong and one-sided road the much
vaunted culture of the 19th century still moves. Ignorance
and superstition are the foundations upon which most men
construct their conception of their own organism and its rela-
tion to the totality of things ; and these palpable facts of
the history of development, which might throw the light
of truth upon them, are ignored. It is true these facts are
not calculated to excite approval among those who assume a
thorough difference between man and the rest of nature, and
who will not acknowledge the animal origin of the human
race. That origin must be a very unpleasant truth to
members of the ruling and privileged castes in those nations
among which there exists an hereditary division of social
classes, in consequence of false ideas about the laws of in-
heritance. It is well known that, even in our day, in many
civilized countries the idea of hereditary grades of rank
goes so far, that, for example, the aristocracy imagine them-
selves to be of a nature totally different from that of or-
dinary citizens, and nobles who commit a disgraceful
offence are punished by being expelled from the caste of
nobles, and thrust down among the pariahs of "vulgar
citizens." What are these nobles to think of the noble blood
which flows in their privileged veins, when they learn that
all human embryos, those of nobles as well as commoners,
during the first two months of development, are scarcely
distinguishable from the tailed embryos of dogs and other
mammals ?

296 THE HISTORY OF CREATIOiN'.

As the object of these pages is solely to further the
general knowledge of natural truths, and to spread, in wider
circles, a natural conception of the relations of man to the
rest of nature, I shall be justified if I do not pay any
regard to the widely-spread prejudice in favour of an ex-
ceptional and privileged position for man in creation, and
simply give here the embryological facts from which the
reader will be able to draw conclusions affirming the
groundlessness of those prejudices. I wish all the more
to entreat him to reflect carefully upon these facts of on-
togeny, as it is my firm conviction that a general knowledge
of them can only promote the intellectual advance, and
thereby the mental perfecting, of the human race.

Amidst all the infinitely rich and interesting material
which lies before us in the ontoo-env of vertebrate animals,
that is, in the history of their individual development, I shall
here confine myself to showing some of those facts which
are of the greatest importance to the Theory of Descent in
general, as well as in its special application to man. Man
is at the beginning of his individual existence a simple egg,
a single little cell, just the same as every animal organism
which originates by sexual generation. The human egg is
essentially the same as that of all other mammals, and can-
not be distino'uished from the e^^ of the hio'her mammals.
The egg represented in Fig. 5 might be that of a man or an
ape as well as of a dog, a horse, or any other mammal Not
only the form and structure, but even the size of the egg in
most mammals is the same as in man, namely, about the
120th part of an inch in diameter, so that the egg under
favorable circumstances, with the naked eye, can just be
I erceived as a small speck. The difterences which really

THE HUMAN EGG. 297

exist between the eggs of different mammals and that of
man do not consist in the form, but in the chemical mixture,
in the molecular composition of the albuminous combination
of carbon, of which the egg essentially consists. These
minute individual differences of all eggs, which depend upon
indirect or potential adaptation (and especially upon the
law of individual adaptation), are indeed not directly per-
ceptible to the exceedingly imperfect senses of man, but are
cognisable through indirect means, as the primary causes of
the difference of all individuals.

The human egg is, like that of all other mammals, a
small globular bladder, which contains all the constituent
parts of a simple organic cell (Fig. 5). The most essential

Fig. 5. — ^The human egg a hundred times en.
larged. a. The kernel speck, or nucleolus (the
so-called germinal spot of the egg), h. Kernel,
or nucleus (the so-called germinal vesicle of the
egg), c. Cell-substance, or protoplasm (so-called
yolk of the egg), d. Cell-membrane (the yolk-
membrane of the egg ; in mammals, on account
of its transparency, called zona pellucida). The
efjofs of other mammals are of the same form.

-'00"

parts of it are the mucous cell-substance, or the protoplasma
(c), which in an egg is called the "yolk," and the cell-kernel,
or nucleus (b), surrounded by it, which is here called by the
special name of the " germinal vesicle." The latter is a deli-
cate, clear, glassy globule of albumen, of about 1 -600th part of
an inch in diameter, and surrounds a still smaller, sharply-
marked, rounded granule (a), the kernel-speck, or the nucle-
olus of the cell (in the egg it is called the " germinal spot").
The outside of the globular egg-cell of a mammal is sur-
rounded by a thick pellucid membrane, the cell-membrane

29^ THE HISTOPvY OF CEEATION.

or yolk-membrane, which here bears the special name of
zona pellucida (d). The eggs of many lower animals
(for example of many Medusse) differ from this in being
naked cells, as the outer covering, or cell-membrane, is
wanting.

As soon as the egg (ovulum) of the mammal has attained
its full maturity, it leaves the ovary of the female, in which
it originates, and passes into the oviduct, and through this
narrow passage into the wider pouch or womb (uterus). If,
meanwhile, the egg is fructified by the male seed (sperm), it
develops itself in this pouch into an embryo, and does not
leave it until perfectly developed and capable of coming
into the world at birth as a young mammaL

The variations of form and transformations which the
fructified egg must go through within the uterus before it
assumes the form of the mammal are exceedingly remark-
able, and proceed from the beginning in man, in precisely
the same way as in the other mammals. At first the fructi-
fied egg of the mammal acts as a single-celled organism,
which is about to propagate independently and increase
itself; for example, an Amoeba (compare Fig. 2, p. 188).
In point of fact the simple egg-cell becomes two, by the
process of cell-division which I have previously described.
There arise from the single germinal spot (the small kernel-
speck of the original simple egg-cell) two new kernel-specks,
and then in like manner, out of the germinal vesicle (the
nucleus), two new cell-kernels. Then, and not until then,
does the globular protoplasma first separate itself by an
equatorial furrow into two halves, in such a manner that
each half encloses one of the two kernels, together with
its kernel-speck. Thus the simple egg-cell, within the

THE CLEAVAGE OF THE YOLK. 299

original cellular membrane, lias become two naked cells,
each possessing its own kernel (Fig. 6).

■..•1

i?

Fig. 6. — First commencement of the development of a mammal's egg, the
so-called " yolk-cleavage " (propagation of the egg-cell by repeated self-
division). A. The egg, by the formation of the first furrow, falls into two
cells. B. These by division fall into four cells. C. These latter have fallen
into eight cells. D. By continued division a globular mass of numerous cells
has arisen.

The same process of cell-division now repeats itself
several times in succession. In this way, from two cells
(Fig. G A) there arise four (Fig. 6 B) ; from four, eight
(Fig. 6 C) ; from eight, sixteen ; from these, thirty-two, etc.
Each time the division of the kernel-speck precedes that of
the kernel ; this, again, precedes that of the cell-substance, or
protoplasma. As the division of the latter always com-
mences with the formation of a superficial annular /it^TOit;,
or cleft, the whole process is usually called the furroiving of
the egg, or yolk-cleavage, and the products of it, that is, the
cells arising from the continued halving, are called the
cleavage spheres. However, the whole process is nothing
more than a simple, oft-repeated division of cells, and the
products of it are actual, naked cells. Finally, through the
continued division or " furrowing " of the mammal's egg,
there arises a mulberry-shaped ball, which is composed of a

300 THE HISTORY OF CBEATION.

great number of small spheres, naked cells, containing
kernels (Fig. 6 D). These cells are the materials out of
which the body of the young mammal is constructed.
Every one of us has once been such a simple mulberry-
shaped ball, composed only of small equi-formal cells.

The further development of the globular lump of cells,
which now represents the young body of the mammal, con-
sists first in its changing into a globular bladder, as fluid
accumulates within it. This bladder is called the germ-
bladder (vesicula blastodermica). Its wall is at first com-
posed of merely equi-formal cells. But soon, at one point on
the wall, arises a disc-shaped thickening, as the cells here
increase rapidly, and this thickening is now the foundation
of the actual body of the germ or embryo, while the other
parts of the germ-bladder serve only for its nutrition. The
thickened disc, or foundation of the embryo, soon assumes an
oblong, and then a fiddle-shaped form, in consequence of its
right and left walls becoming convex (Fig. 7, p. 804). At
this stage of development in the first form of their germ or
embryo, not only all mammals, including man, but even all
vertebrate animals in general — birds, reptiles, amphibious
animals, and fishes — can either not be distinguished from
one another at all, or only by very unessential differences,
such as the arrangement of the egg-coverings. In all the
whole body consists of nothing but a quite simple, oblong,
oval, or violin-shaped thin disc, which is composed of three
closely connected membranes or plates, lying one above
another. Each of the three plates or layers of the germ
consists simply of cells all exactly like one another; but
each layer has a different function in the building up of the
vertebrate animal body. Out of the upper or outer germ-

DIFFERENTIATION OF THE CELLS. 301

layer arises solely the outer skin (epidermis), together
with the central parts of the nervous system (spinal marrow
and brain) ; out of the lower or inner layer arises only
the inner delicate skin (epithelium) which lines the whole
intestinal tube from the mouth to the anus, together with
all tlie glands connected with it (lung, liver, salivary
glands, etc) ; out of the middle germ-layer lying between
the two others arise all the other organs, muscles, bones,
blood-vessels. Xow, the processes by which the various and
exceedingly complicated parts of the fully-formed body of
vertebrate animals arise out of such simple material — out of
the three germ -layers composed only of cells — are, in the
first place, the repeated division, and consequently the
increase of cells ; in the second place, the division of labour
or differentiation of these cells; and thirdly, the union of
the variously developed or differentiated cells, for the
formation of the different organs. Thus arises the gradual
progress or perfecting which can be traced step by step
in the development of the embryonic body. The simple
embryonic cells, which are to constitute the body of the
vertebrate animal, stand in the same relation to each other
as citizens who v/ish to found a state. Some take to one
occupation, others to another, and work together for the
good of the whole. By this division of labour, or differen-
tiation, and the perfecting (the organic progress) which is
connected with it, it becomes possible for the whole state to
accomplish undertakings which would have been impossible
to the single individual. The whole body of the vertebrate
animal, like every other many-celled organism, is a republi-
can state of cells, and consequently it can accomplish organic
functions which the individual cell, as a solitary individual

302 THE HISTORY OF CREATION.

(for example, an Amoeba, or a single-celled plant), could
never perform.

No sensible person supposes that carefully devised insti-
tutions, which have been established for the good of the
whole, as well as for the individual, in every human state,
are the results of the action of a personal and supernatural
Creator, acting for a definite purpose. On the contrary,
every one knows that these useful institutions of organiza-
tion in the state are the consequences of the co-operation of
the individual citizens and tlieir common government, as
well as of adaptation to the conditions of existence of the
outer world. Just in the same way we must judge of the
many-celled organism. In it also all the useful arrangements
are solely the natural and necessary result of the co-operation,
differentiation, and perfecting of the individual citizens —
the cells — and by no means the artificial arrangements of a
Creator acting for a definite purpose. If we rightly consider
this comparison, and pursue it further, we can distinctly
see the perversity of that dualistic conception of nature
which discovers the action of a creative plan of construction
in the various adaptations of the organization of living
things.

Let us pui'sue the individual development of the verte-
brate animal body a few stages further, and see what is next
done by the citizens of this embryonic organism. In the
central line of the violin-shaped disc, which is composed of
the three cellular germ-layers, there arises a straight deli-
cate furrow, the so-called " primitive streak," by which the
violin-shaped body is divided into two equal lateral halves —
a right and a left part or " antimer." On both sides of that
streak or furrow, the upper or external germ-layer rises in

DEVELOPMENT OF THE BPvAlN. 303

the form of a longitudinal fold, and both folds then grow
together over the furrow in the central line, and thus form
a cylindrical tube. This tube is called the marrow-tube, or
medullary canal, because it is the foundation of the central
nervous system, the spinal Tnarrow (medulla spinalis). At
first it is pointed both in front and behind, and it remains so
for life in the lowest vertebrate animal, the brainless, skull-
less Lancelet (Amphioxus). But in all other vertebrate
animals, which we distinguish from the latter as skulled
animals, or Craniota, a difference between the fore and
hinder end of the marrow tube soon becomes visible, the
fore end becoming dilated, and changing into a roundish
bladder, the foundation of the brain.

In all Craniota, that is, in all vertebrate animals possess-
ing skull and brain, the brain, which is at first only the
bladder-shaped dilatation of the anterior end of the spinal
marrow, divides into five bladders lying one behind the
other, four superficial, transverse in-nippings being formed.
These five hrain-bladders, out of which afterwards arise all
the different parts of the intricately constructed brain, can
be seen in their original condition in the embryo represented
in Fig. 7. It is just the same whether we examine the em-
bryo of a dog, a fowl, a lizard, or any other higher vertebrate
animal. For the embryos of the different skulled animals
(at least the three higher classes of them, the reptiles, birds
and mammals) cannot be in any way distinguished at the
stage represented in Fig. 7. The whole form of the body is
as yet exceedingly simple, being merely a thin, leaf-like disc.
Face, legs, intestines, etc., are as yet completely wanting.
But the five bladders are already quite distinct from one
another.

04

THE HISTORY OF CEEATION.

Fig. 7. — Embryo of a mammal or bird, in
which the live brain-bladders have just com«
menced to develop, v. Fore brain, z. Twixt braiiu
m. Mid brain, h. Hind brain, n. After brain,
p. Spinal-marrow, a. Eye-bladders. w. Primi-
tive vertebrse. d. Spinal-axis or notochord.

The first bladder, the fore brain (a),
is in so far the most important that
it principally forms the hemispheres of
the so-called larger brain (cerebrum),
that part which is the seat of the
higher mental activities. The more
these activities are developed in the
series of vertebrate animals, the more
do the two lateral halves of the fore
brain, or the hemispheres, grow at the
expense of the other bladders, and
overlap them in front and from above. In man, where they
are most strongly developed, agreeing with his higher men-
tal activity, they eventually almost entirely cover the other
parts from above (compare Plates II. and III.) The second
bladder, the twixt brain (z), forms that portion of the
brain which is called the centre of sight, and stands in
the closest relation to the eyes (a), which grow right and
left out of the fore brain in the shape of two bladders, and
later lie at the bottom of the twixt brain. The thir dhlsidder,
the noid brain (pn), for the most part vanishes in the
formation of the so-called four bulbs, a bossy portion of
the brain, which is strongly developed in reptiles and
birds (Fig. E, F, Plate II.), whereas in mammals it recedes

THE FIVE BLADDERS OF THE BUAIN. 305

much more (Fig. G, H, Plate III.). The fourth bladder, the
kind brain (h), forms the so-called little hemispheres, to-
gether with the middle part of the small Wain (cerebellum),
a part of the brain as to the function of which the most con-
tradictory conjectures are entertained, but which seems prin-
cipally to regulate the co-ordination of movements. Lastly;
the fifth bladder, the after brain (n), develops into that
very important part of the central nervous system which
is called the prolonged marrow (medulla oblongata). It
is the central organ of the respiratory movements, and of
other important functions, and an injury to it immediately
causes death, whereas the large hemispheres of the fore brain
(or the organ of the " soul," in a restricted sense) can be re-
moved bit by bit, and even completely destroyed, without
causing the death of the vertebrate animal — only its higher
mental activities disappearing in consequence.

These five brain bladders, in all vertebrate animals which
possess a brain at all, are originally arranged in the same
manner and develop gradually in the different groups so
differently, that it is afterwards very difficult to recognize
the corresponding parts in the fully-developed brains. In
the early stage of development which is represented in
Fig. 7, it seems as yet quite impossible to distinguish the
embryos of the different mammals, birds, and reptiles, from
one another. But if we compare the much more developed
embryos on Plates II. and III. with one another, we can
clearly see an inequality in their development, and especi-
ally it will be perceived that the brain of the two mammals
(fi and H) already strongly differ from that of birds {F) and of
reptiles {E). In the two latter the mid brain predominates,
but in the former the fove brain. Even at this sta^xe the

306 THE HISTOEY OF CREATION.

brain of the bird (F) is scarcely distinguishable from that of
the tortoise (E), and in like manner the brain of the dog {G)
is as yet almost the same as that of man (H). If, on the
other hand, we compare the brains of these four vertebrate
animals in a fully developed condition, -vve find them so
very different in all anatomical particulars, that we cannot
doubt for a moment as to which animal each brain belongs.

I have here explained the original equality, the gTadual
commencement, and the ever increasing separation or
differentiation of the embryos in the different vertebrate
animals, taking the brain as a special example, just because
this organ of the soul's activity is of special interest. But T
might as well have discussed in its stead the heart, or the
liver, or the limbs, in short, any other part of the body, since
the same wonder of creation is here ever repeated, namely,
this, that all parts are originally the same in the different
vertebrate animals, and that the variations by which the
different classes, orders, families, genera, etc., differ and
deviate from one another, are only gradually developed.

There are certainly few parts of the body which are so
differently constructed as the Imihs or extremities of the
vertebrate animals. Now, I wish the reader to compare in
Fig. A — ^on Plates II. and III, the four extremities (hv) of
the embryos with one another, and he will scarcely be able
to perceive any important differences between the human
arm (H hv), the wing of a bird {F hv), the slim foreleg of a
dog {G hv), and the plump foreleg of the tortoise (E hv). In
comparing the hinder extremities (hh) in these figures he
v,i\\ find it equally difficult to distinguish the leg of a man
{Hhh), of a bird (Fhh), the hind-leg of a dog (Ghh), and
that of a tortoise (Ehh). The fore as v ell as the hinder

PI. II.

Germs or Embryos

^ * -«,-'W*«fy^-^

t^ -^K»^rj,l

/

^4 ^S?'

"«s

-5a.

^^

'v..

^^\

*v¥~

'/ctV,:,

^:?^- :^ K

%ft£^>

?V-v .

5

"■-?

|r .—«

/

vA^^j,

^.

%SJi-

1 i-

— rw —

"^f

mm:-

Fig K
Chick 'MfMySt

?:'. Fore-brain, z. Twixt-brain. m. Mid-brain, /i. Hind-Brain.
n. After-brain, w. Spine, r. Spinal-cord.

of four Vertebrates.

y?^.

PI. III.

?c:m^ivM^^::^^^^smmmms^!ms;!^sm'' -■'■.'^ ■■!~'~."---:- ^^-^^--x.^^'^.-fs-as.Vy-'-'^'-'j'f.iiSi;

h

\ '7! T'fl

'^wm^

•1

)

t

I , 1 - --

} i

M If I"

i

^4^i^M'

A.

*- ^li

V,

)&.

v;

li f

:f?8¥/^'SS

( IV V/aoV

V \V^*?1CS ;

i

^'«£>«-''' .

/7; \

'-f ''

4-^s

( J

, 7'^x-

¥-

^^:^.j^^-tSmffi'

W"^^

-4^^

-?

I

fe /

Nail

««. Nose, a. Eyes. ^. Ear. /^ /^ >^. Gili-arches. s. Tail.

12 3

<^t;. Fore-leg. M. Hind-leg.

THE GILL- ARCHES OF MAN. 307

extremities are as yet short, Ifroad lumps, at the ends of
which the foundations of the five toes are placed, connected
as yet by a membrane. At a still earlier stage (Fig. A — D)
the five toes are not marked out at all, and it is quite im-
possible to distinguish even the fore and hinder extremities
from one another. The latter, as well as the former, are
nothing but simple roundish processes, which have grown
out of the side of the trunk. At the very early stage
represented in Fig. 7 they are completely wanting, and the
whole embryo is a simple trunk without a trace of limbs.

I wish especially to draw attention in Plates II. and
III., which represents embryos in early stages of develop-
ment (Fig. A — D) — and in which we are not able to recog-
nize a trace of the full-grown animal — to an exceedingly
important formation, which originally is common to all
vertebrate animals, but which at a later period is trans-
formed into the most different organs. Every one surely
knows the gill-arches of fish, those arched bones which
lie behind one another, to the number of three or four,
on each side of the neck, and which support the gills,
the respiratory organs of the fish (double rows of red leaves,
which are popularly called " fishes' ears.") Now, these gill-
arches originally exist exactly the same in man {D), in dogs
(C), in fowls (B), and in tortoises (A), as well as in all othei
vertebrate animals. (In Fig. A — D the three giU-arches of
the right side of the neck are marked k^ k^ k^). Now, it
is only in fishes that these remain in their original form, and
develop into respiratory organs. In the other vertebrate
animals they are partly employed in the formation of the
face (especially the jaw apparatus), and partly in the forma-
tion of the or^an of hearin^j.

3o8 THE HISTOKY OF CREATION.

Finally, when comparing the embryos on Plates II. and III.,
we must not fail to give attention again to the huTnan
tail (s), an organ which, in the original condition, man
shares with all other vertebrate animals. The discovery of
tailed men was long anxiously expected by many monistic
philosophers, in order to establish a closer relationship
between man and the other mammals. And in like manner
their dualistic opponents often maintained with pride that
-the complete want of a tail formed one of the most important
bodily distinctions between men and animals, though they
did not bear in mind the many tailless animals which really
exist. Now, man in the first months of development pos-
sesses a real tail as well as his nearest kindred, the tailless
apes (orang-outang, chimpanzee, gorilla), and vertebrate
animals in general. But whereas, in most of them — for
example, the dog {C, G^)^in the course of development it
always grows longer, in man (Fig. D, H) and in tailless
mammals, at a certain period of development, it degenerates
and finally completely disappears. However, even in fully
developed men, the remnant of the tail is seen in the three,
four, or five tail vertebrae (vertebrae coccygeoe) as an
aborted or rudimentary organ, which forms the hinder or
lower end of the vertebral column (p. 289).

Most persons even now refuse to acknowledge the most
important deduction of the Theory of Descent, that is, the
palaeontological development of man from ape-like, and
through them from still lower, mammals, and consider such
a transformation of organic form as impossible. But, I
ask, are the phenomena of the individual development of
man, the fundamental features of which I have here given,
in any way less wonderful ? Is it not in the highest

THE RECAPITULATION HYPOTHESIS. 309

degree remarkable that all vertebrate animals of the most
different classes — fishes, amphibious animals, reptiles, birds,
and mammals — in the first periods of their embryonic
development cannot be distinguished at all, and even much
later, at a time when reptiles and birds are already distinctly
different from mammals, that the dog and the man are
almost identical ? Verily, if we compare those two series of
development with one another, and ask ourselves which of
the two is the more wonderful, it must be confessed that
ontogeny J or the short and quick history of development of
the individual, is much more mysterious than i~>hylogeny, or
the long and slow history of development of the tribe. For
one and the same grand change of form is accomplished by
the latter in the course of many thousands of years, and by
the former in the course of a few months. Evidently this
most rapid and astonishing transformation of the individual
in ontogenesis, which we can actually point out at any
moment by direct observation, is in itself much more
wonderful and astonishing than the corresponding, but
much slower and gradual transformation which the long
chain of ancestors of the same individual has gone through
in phylogenesis.

The two series of organic development, the ontogenesis of
the individual and the phylogenesis of the tribe to which
it belongs, stand in the closest causal connection with each
other. I have endeavoured, in the second volume of the
" General Morphology," * to establish this theory in detail,
as I consider it exceedingly important. As I have there
shown, ontogenesis, or the develoj^TYient of the individual, is a
short and quick repetition (recapitulation) of phylogenesis,
or the development of the tribe to ivhich it belongs, determined

3IO THE HISTORY OF CEEATION.

hy the laii's of inheritance and adaptation ; by tribe I
mean the ancestors which form the chain of progenitors of
the individual concerned. (Gen. Morph. ii. p. 110-147, 371.)
In this intimate connection of ontogeny and phylogeny, I
see one of the most important and irrefutable proofs of the
Theory of Descent. No one can explain these phenomena
unless he has recourse to the laws of Inheritance and
Adaptation; by these alone are they explicable. These
laws, which we have previously explained, are the laws of
abbreviated, of honiochronic, and of homotojnc inheritance,
and here deserve renewed consideration. As so high and
complicated an organism as that of man, or the organism of
every other mammal, rises upwards from a simple cellular
state, and as it progresses in its differentiation and per-
fecting it passes through the same series of transform-
ations which its animal progenitors have passed through,
during immense spaces of time, inconceivable ages ago. I
have already pointed out this extremely important parallel-
ism of the development of individuals and tribes (p. 10).
Certain very early and low stages in the development of
man, and the other vertebrate animals in general, correspond
completely in many points of structure with conditions
which last for life in the lower fishes. The next phase
which follows upon this presents us with a change of the
fish-like being into a kind of amphibious animal At a later
period the mammal, with its special characteristics, de-
velops out of the amphibian, and we can clearly see, in the
successive stages of its later development, a series of steps of
progressive transformation which evidently correspond with
the difterences of different mammalian orders and families.
Now, it is precisely in the same succession that we also see

THE SERIES OF LIVING SPECIES. 3 II

the ancestors of man, and of the higher mammals, appear
one after the other in the earth's history ; first fishes, then
amphibians, later the lower, and at last the higher mam-
mals. Here, therefore, the embryonic development of
the individual is completely parallel to the palseontological
development of the whole tribe to which it belongs, and this
exceedingly interesting and important phenomenon can be
explained only by the interaction of the laws of Inheritance
and Adaptation.

The example last mentioned, of the parallelism of the
palseontological and of the individual developmental series,
now directs our attention to a third developmental series,
which stands in the closest relations to these two, and which
likewise runs, on the whole, parallel to them. I mean that
series of development of forms which constitutes the object
of investigation in comiioarative anoiomy, and which I will
briefly call the systematic developTnental series of species.
By this we understand the chain of the different, but re-
lated and connected forms, which exist side hy side at any
one period of the earth's history; as for example, at the
present moment. While comparative anatomy compares the
different forms of fully-developed organisms with one
another, it endeavours to discover the common prototypes
which underlie, as it were, the manifold forms of kindred
genera, classes, etc., and which are more or less concealed by
their particular differentiation. It endeavours to make out
the series of progressive steps which are indicated in the
different degrees of perfection of the divergent branches of
the tribe. To make use again of the same particular in-
stance, comparative anatomy shows us how the individual
organs and systems of organs in the tribe of vertebrate

312 THE HISTORY OF CREATION.

animals — in the different classes, families, and species of it
— have unequally developed, differentiated, and perfected
themselves. It shows us how far the succession of classes
of vertebrate animals, from the Fishes upwards, through the
Amphibia to the Mammals, and here again, from the
lower to the higher orders of Mammals, forms a progressive
series or ladder. This attempt to establish a connected
anatomical developmental series we may discover in the
works of the great comparative anatomists of all ages —
in the works of Goethe, Meckel, Cuvier, Johannes Miiller,
Gegenbaur, and Huxley.

The developmental series of mature forms, which com-
parative anatomy points out in the different diverging and
ascending steps of the organic system, and which we call
the systematic developmental series, is parallel to the
palseontological developmental series, because it deals with
the result of pal^eontolgical development, and it is parallel
to the individual developmental series, because this is
parallel to the palseontological series. If two parallels are
parallel to a third, they must be parallel to one another.

The varied differentiation, and the unequal degree of per-
fecting which comparative anatomy points out in the
developmental series of the System, is chiefly determined
by the ever increasing variety of conditions of existence to
which the different groups adapt themselves in the struggle
for life, and by the different degrees of rapidity and com-
pleteness with which this adaptation has been effected.
Conservative groups wdiich have retained their inherited
peculiarities most tenaciously remain, in consequence, at the
lowest and rudest stage of development. Those groups pro-
gressing most rapidly and variously, and which have adapted

THE THREE SERIES PARALLEL. 313

themselves to changed conditions of existence most readily
have attained the highest degree of perfection. The
further the organic world developed in the course of the
earth's history, the greater must the gap between the lower
conservative and the higher progressive groups have be-
come, as in fact may be seen too in the history of nations
In this way also is explained the historical fact, that the
most perfect animal and vegetable groups have developed
themselves in a comparatively short time to a considerable
height, while the lowest or most conservative groups have
remained stationary throughout all ages in their original
simple stage, or have progressed, but very slowly and
gradually. The series of man's progenitors clearly shows
this state of things. The sharks of the present day are still
very like the primary fish, which are among the most
ancient vertebrate progenitors of man, and the lowest
amphibians of the present day (the gilled salamanders and
salamanders) are very like the amphibians which first de-
veloped themselves out of fishes. So, too, the later ances-
tors of man, the Monotremata and Marsupials, the most
ancient mammals, are at the same time the most imperfect
animals of the class which still exist.

The laws of inheritance and adaptation known to us are
completely suflacient to explain this exceedingly important
and interesting phenomenon, which may be briefly desig-
nated as the parallelism of individual, of palceontological,
and of systematic development. No opponent of the Theory
of Descent has been able to give an explanation of this ex-
tremely wonderful fact, whereas it is perfectly explained,
according to the Theory of Descent, by the laws of Inherit-
ance and Adaptation,

314

THE HISTORY OF CREATION.

If we examine this parallelism of the three organic
series of development more accurately, we have to add
the following special qualifications. Ontogeny, or the
history of the individual development of every organism
(embryology and metamorphology), presents us with a
simple unhrancJiing or graduated chain of forms ; and so it
is with that portion of phytogeny which comprises the
palseontological history of development of the direct ancestors
only of an individual organism. But the ivhole of jpliylogeny
— which meets us in the natural system of every organic
tribe or phylum, and which is concerned with the investi-
gation of the palseontological development of all the
branches of this tribe — forms a branching or tree-shaped
developmental series, a veritable pedigree. If we examine
and compare the branches of this pedigree, and place them
together according to the degree of their differentiation and
perfection, we obtain the tree-shaped, branching, systematic
developmental series of comparative anatomy. Strictly
speaking, therefore, the latter is parallel to the whole of
phylogeny, and consequently is only partially parallel to
ontogeny ; for ontogeny itself is parallel only to a portion
of phylogeny.

All the phenomena of organic development above dis-
cussed, especially the threefold genealogical parallelism,
and the laws of differentiation and progress, which are
evident in each of these three series of organic development,
and, further, the whole history of rudimentary organs, are
exceedingly important proofs of the truth of the Theory of
Descent. For by it alone can they be explained, whereas
its opponents cannot even offer a shadow of an explanation
of them. Without the Doctrine of Filiation, the fact of

LAMARCK S THEORY is^ECESSi.RY. 315

organic development in general cannot be understood. We
should therefore, for this reason alone, be forced to accept
Lamarck's Theory of Descent, even if we did not possess
Darwin's Theory of Selection.

3l6 THE HISTORY OF CSEATION-

CHAPTER XIII.

THEORY OF THE DEVELOPMENT OF THE UNIVERSE
AND OF THE EARTH. SPONTANEOUS GENERA-
TION. THE CARBON THEORY. THE PLASTID
THEORY.

History of the Development of the Earth. — Kant's Theory of the Develop,
ment of the Universe, or the Cosmological Gas Theory. — Development
of Suns, Planets, and Moons. — First Origin of Water. — Comparison
of Oi'ganisms and Anorgana. — Organic and Inorganic Substances. —
Degrees of Density, or Conditions of Aggregation, — Albuminous
Combinations of Carbon. — Organic and Inorganic Forms. — Crystals
and Formless Organisms without Organs. — Stereometrical Fundamental
Forms of Crystals and of Organisms. — Organic and Inorganic Forces.
— ^Vital Force. — Growth and Adaptation in Crystals and in Organisms.
— Formative Tendencies of Crystals. — Unity of Organic and In.
organic Nature. — Spontaneous Generation, or Archigony. — Autogony
and Plasmogony. — Origin of Monera by Spontaneous Generation. —
Origin of Cells from Monera.— The Cell Theory.— The Plastid Theory.
— Plastids, or Structural-Units. — Cytods and Cells. — Four Different
Kinds of Plastids.

In our considerations hitherto we have endeavoured to
answer the question, " By what causes have new species of
animals and plants arisen out of existing species?" We
have answered this question according to Darwin's theory,
that natural selection in the struggle for existence — that is,
the interaction of the laws of Inheritance and Adaptation
— is completely sufficient for producing mechanically the

ADHESION OF A DIVINE. 317

endless variety of the different animals and plants, which
have the appearance of being organized according to a plan
for a definite purpose. Meanwhile the question must have
already repeatedly presented itself to the reader, how did
the first organisms, or that one original and primaeval organ-
ism arise, from which we derive all the others ?

This question Lamarck ^ answered by the hypothesis
of spontaneous generation, or archigony. But Darwin
passes over and avoids this subject, as he expressly
remarks that he has " nothing to do with the origin of
the soul, nor with that of life itself" At the conclusion
of his work he expresses himself more distinctly in the
following words : — " I imagine that probably all organic
beinofs which ever lived on this earth descended from
some primitive form, which was first called into life by
the Creator." Moreover, Darwin, for the consolation of
those who see in the Theory of Descent the destruction of
the whole "moral order of the universe," appeals to the
celebrated author and divine who wrote to him, that
" he has gi^adually learnt to see that it is just as noble a
conception of the Deity to believe that he created a few
original forms capable of self-development into other and
needful forms, as to believe that he required a fresh act
of creation to supply the voids caused by the action of his
laws."

Those to whom the belief in a supernatural creation is an
emotional necessity may rest satisfied with this conception.
They may reconcile that belief with the Theory of Descent ;
for in the creation of a single original organism possessing
the capability to develop all others out of itself by inherit-
ance and adaptation, they can really find much more cause
15

3l8 TPIE HISTORY OF CREATION.

for admiring the power and wisdom of the Creator than in
the independent creation of different species.

If, taking this point of view, we were to explain the
origin of the first terrestrial organisms, from which all the
others are descended, as due to the action of a personal
Creator acting according to a definite plan, we should of
course have to renounce all scientific knowledge of the
process, and pass from the domain of true science to the
completely distinct domain of poetical faith. By assuming
a supernatural act of creation we should be taking a leap
into the inconceivable. Before we decide upon this latter
step, and thereby renounce all pretension to a scientific
knowledge of the process, we are at all events in duty
bound to endeavour to examine it in the light of a mechani-
cal hypothesis. We must at least examine whether this
process is really so wonderful, and whether we cannot form
a tenable conception of a completely non-miraculous origin
of the first primary organism. We might then be able
entirely to reject miracle in creation.

It will be necessary for this purpose, fii'st of all, to go
back further into the past, and to examine the history of
the creation of the earth. Going back still further, we
shall find it necessary to consider the history of the crea-
tion of the whole universe in its most general outlines.
All my readers undoubtedly know that from the struc-
ture of the earth, as it is at present known to us, the
notion has been derived, and as yet has not been refuted,
that its interior is in a fiery fluid condition, and that the
firm crust, composed of difierent strata, on the surface
of which organisms are living, forms only a very thin
pellicle or shell round the fiery fluid centre. We have

DEVELOPMENT OF THE EARTH. 319

arrived at this idea by different confirmatory experi-
ments and reasonings. In the first place, the observation
that the temperature of tlie earth's crust continually increases
towards the centre is in favour of this supposition. The
deeper we descend, the greater the warmth of the ground,
and in such proportion, that with every 100 feet the
temperature increases about one degree. At a depth of
six miles, therefore, a heat of loOO*^ would be attained, suffi-
cient to keep most of the firm substances of our earth's crust
in a molten, fiery, fluid state. This depth, however, is only
the 286th part of the whole diameter of the earth (1717
miles). We further know that springs which rise out of a
considerable depth possess a very high temperature, and
sometimes even throw water up to the suiface in a boiling
state. Lastly, very important proofs are furnished by
volcanic phenomena, the eruption of fiery fluid masses of
stone bursting through certain parts of the earth's crust.
All these phenomena lead us with gi'eat certainty to the im-
portant assumption that the firm crust of the earth forms
only quite a small fraction, not nearly the one-thousandth
part of the whole diameter of the terrestrial globe, and that
the rest is still for the most part in a molten or fiery
fluid state.

Now if, starting with this assumption, we reflect on the
ancient history of the development of the globe, we are
logically carried back a step further, namely, to the assump-
tion that at an earlier date the whole earth was a fiery fluid
body, and that the formation of a thin, stiffened crust on the
surface was only a later process. Only gradually, by
radiating its intrinsic heat into the cold space of the universe,
has the surface of the glowing ball become condensed into

320 THE HISTORY OF CREATION.

a thin crust. That the temperature of the earth in remote
times was much higher than it is now, is proved by
many phenomena. Among other things, this is rendered
probable by the equal distribution of organisms in remote
times of the earth's history. While at present, as is well
known, the different populations of animals and plants
correspond to the different zones of the earth and their
appropriate temperature, in earlier times this was distinctly
not the case.

We see from the distribution of fossils in the remoter
ages, that it was only at a very late date, in fact, at a com-
paratively recent period of the organic history of the
earth (at the beginning of the so-called csenolithic or tertiary
period), that a separation of zones and of the corresponding
organic populations occurred. During the immensely long
primary and secondary periods, tropical plants, which
require a very high degree of temperature, lived not only
in the present torrid zone, under the equator, but also in
the present temperate and frigid zones. Many other
phenomena also demonstrate a gradual decrease of the tem-
perature of the globe as a whole, and especially a late and
gradual cooling of the earth's crust about the poles. Bronn,
in his excellent " Investigations of the Laws of Development
of the Organic World," has collected numerous geological and
paliBontological proofs of this fact.

These phenomena and the mathematico-astronomical know-
ledge of the structure of the universe justify the theory that,
inconceivable ages ago, long before the first existence of
organisms, the whole earth was a fiery fluid globe. Now, this
theory corresponds with the grand theory of the origin of
the universe, and especially of our planetary system, which,

GASEOUS CONDITION OF THE UNIVERSE. 32 1

on the ground of mathematical and astronomical facts, was
put forward in 1755 by our critical philosopher Kant,^^
and was later more thoroughly established by the celebrated
mathematicians, Laplace and Herschel. This cosmogeny, or
theory of the development of the universe, is now almost
universally acknowledged; it has not been rej^laced by a
better one, and mathematicians, astronomers, and geologists
have continually, by various arguments, strengthened its
position.

Kant's cosmogeny maintains that the whole universe, in-
conceivable ages ago, consisted of a gaseous chaos. All the
substances which are found at present separated on the
earth, and other bodies of the universe, in different con-
ditions of densit}^ — in the solid, semi-fluid, liquid, and elastic
fluid or gaseous states of aggregation — originally constituted
together one single homogeneous mass, equally filling up the
space of the universe, which, in consequence of an extremely
high degree of temperature, was in an exceedingly thin
gaseous or nebulous state. The millions of bodies in
the universe which at present form the different solar
systems did not then exist. They originated only in con-
sequence of a universal rotatory movement, or rotation,
during which a number of masses acquired greater density
than the remaining gaseous mass, and then acted upon the
latter as central points of attraction. Thus arose a separa-
tion of the chaotic primary nebula, or gaseous universe, into
a number of rotating nebulous spheres, which became
more and more condensed. Our solar system was such a
gigantic gaseous or nebulous ball, all the particles of which
revolved round a common central point, the solar nucleus.
The nebulous ball itself, like all the rest, in consequence

322 THE HISTOEY OF CREATION.

of its rotatory movement, assumed a spheroidal or a flattened
globular form.

While the centripetal force attracted the rotating particles
nearer and nearer to the firm central point of the nebulous
ball, and thus condensed the latter more and more, the cen-
trifugal force, on the other hand, always tended to separate
the peripheral particles further and further from it, and to
hurl them off. On the equatorial sides of the ball, which
was flattened at both poles, this centrifugal force was
strongest, and as soon as, by increase of density, it attained
predominance over the centripetal force, a circular nebulous
ring separated itself from the rotating ball. This nebulous
ring marked the course of future planets. The nebulous
mass of the ring gradually condensed, and became a planet,
which revolved round its own axis, and at the same
time rotated round the central body. In precisely the
same manner, from the equator of the planetary mass, as
soon as the centrifugal force gained predominance over
the centripetal force, new nebulous rings were ejected,
which moved round the planets as the latter moved- round
the sun. These nebulous rings, too, became condensed into
rotating balls. Thus arose the moons, only one of which
moves round our earth, whilst four move round Jupiter, and
six round Uranus. The ring of Saturn still shows us a moon
in its early stage of development. As by increasing refrigera-
tion these simple processes of condensation and expulson
repeated themselves over and over again, there arose the
different solar systems, the planets rotating round their
central suns, and the satellites or moons moving round their
planets.

The original gaseous condition of the rotating bodies of

KANT'S GAS THEORY. 323

the universe gradually changed, by increasing refrigeration
and condensation, into the fiery fluid or molten state of
aggregation. By the process of condensation, a great
quantity of heat was emitted, and the rotating suns, planets,
and moons, soon changed into glowing balls of fire, like
gigantic drops of melted metal, which emitted light and
heat. By loss of heat, the melted mass on the surface of the
fiery fluid ball became further condensed, and thus arose a
thin, firm crust, which enclosed a fiery fluid nucleus. In all
essential respects our mother earth probably did not differ
from the other bodies of the universe.

In view of the object of these pages, it will not be of
especial interest to follow in detail the history of the natural
creation of the universe, with its different solar and planet-
ary systems, and to establish it mathematically by the dif-
ferent astronomical and geological proofs. The outlines of it,
which I have just mentioned, must be sufficient here, and
for further details I refer to Kant's* " General History of
Nature and Theory of the Heavens." ^^ I will only add
that this wonderful theory, which might be called the cosnio-
logical gas theory, harmonizes with all the general series of
phenomena at present known to us, and stands in no irre-
concilable contradiction to any one of them. Moreover, it
is purely mechanical or monistic, makes use exclusively of
the inherent forces of eternal matter, and entirely excludes
every supernatural process, every prearranged and conscious
action of a personal Creator. Kant's Cosmological Gas
Theory consequently occupies a similar supreme position in
Anorganology, especially in Geology, and forms the crown
of our knowledge in that department, in the same

• ((

Allgemeine Naturgeschichte und Theorie des Hinimela.''

324 THE HISTORY OF CREATION,

way as Lamarck's Theory of Descent does in Biology, and
especially in Anthropology. Both rest exclusively upon
mechanical or unconscious causes (causse efficientes), in no
case upon prearranged or conscious causes (causse finales).
(Compare above, p. 100-106). Both therefore fulfil all the
demands of a scientific theory, and consequently will remain
generally acknowledged until they are replaced by better
ones.

I will, however, not deny that Kant's grand cosmogeny
has some weak points, which prevent our placing the same
unconditional confidence in it as in Lamarck's Theory of
Descent. The notion of an original gaseous chaos filling
the whole universe presents great difficulties of various
kinds. A great and unsolved difficulty lies in the fact that
the Cosmological Gas Theory furnishes no starting-point at
all in explanation of the first impulse which caused the
rotary motion in the gas-filled universe. In seeking for
such an impulse, we are involuntarily led to the mistaken
questioning about a " first beginning." We can as little
imagine a first beginning of the eternal phenomena of the
motion of the universe as of its final end.

The universe is unlimited and immeasurable in both
space and time. It is eternal, and it is infinite. Nor can
we imagine a beginning or end to the uninterrupted and
eternal motion in which all particles of the universe are
always engaged. The great laws of the conservation of
force ^ and the conservation of matter, the foundations
of our whole conception of nature, admit of no other supposi-
tion. The universe, as far as it is cognisable to human
capability, appears as a connected chain of material phe-
nomena of motion, necessitating a continual change of

THE FIRST CRUST OF THE EAKTH. 325

forms. Every form, as the temporary result of a multi-
plicity of phenomena of motion, is as such perishable, and
of limited duration. But, in the continual change of forms,
matter and the motion inseparable from it remain eternal
and indestructible.

Now, although Kant's Cosmological Gas Theory is not able
to explain the development of motion in the whole universe
in a satisfactory manner, beyond that gaseous state of chaos,
and although many other weighty considerations may be
brought forward against it, especially by chemistry
and geology, yet we must on the whole acknowledge its
great merit, inasmuch as it explains in an excellent
manner, by due consideration of development, the whole
structure of all that is accessible to our observation, that is,
the anatomy of the solar systems, and especially of our
planetary system. It may be that this development was
altogether different from what Kant supposes, and our
earth may have arisen by the aggregation of numberless
small meteorides, scattered in space, or in any other manner,
but hitherto no one has as yet been able to establish any
other theory of development, or to offer one in the place
of Kant's cosmogeny.

After this general glance at the monistic cosmogeny, or
the non-miraculous history of the development of the
universe, let us now return to a minute fraction of it, to our
mother earth, which we left as a ball flattened at both poles
and in a fiery fluid state, its surface having condensed by
becoming cooled into a very thin firm crust. The crust, on
first cooling, must have covered the whole surface of the
terrestrial sphere as a continuous smooth and thin shell.
But soon it must have become uneven and hummocky ; for.

320 THE HISTORY OF OKEATION.

since during the continued cooling, the fiery fluid nucleus
became more and more condensed and contracted, and
consequently the diameter of the earth diminished, the
thin cold crust, which could not closely follow the softer
nuclear mass, must have fallen in, in many places. An
empty space would have arisen between the two, had not
the pressure of the outer atmosphere forced down the
fragile crust towards the interior, breaking it in so doing.
Other unevennesses probably arose from the fact that, in
different parts, the cooled crust during the process of
refrigeration contracted also itself, and thus became fissured
with cracks and rents. The fiery fluid nucleus flowed up
to the external surface through these cracks, and again
became cooled and stiff". Thus, even at an early period there
arose many elevations and depressions, which were the fii^st
foundations of mountains and valleys.

After the tempei^ature of the cooled terrestrial ball had
fallen to a certain degree, a very important new process was
effected, namely, the first origin of water. Water had until
then existed only in the form of steam in the atmosphere
surrounding the globe. The water could evidently not con-
dense into a state of fluid drops until the temperature of the
atmosphere had considerably decreased. Now, then, there
began a further transformation of the earth's crust by the force
of water. It continually fell in the form of rain, and in that
form washed down the elevations of the earth's crust,
filling the depressions with the mud carried along, and, by
depositing it in layers, it caused the extremely important
neptunic transformations of the earth's crust, which have
continued since then uninterruptedly, and which in our
next chapter we shall examine a little more closely.

SPONTANEOUS GENERATION. 327

It was not till the earth's crust had so far cooled that the
water had condensed into a fluid form, it was not till the
hitherto dry crust of the earth had for the first time become
covered with liquid water, that the origin of the first
organisms could take place. For all animals and all plants —
in fact, all organisms — consist in great measure of fluid
water, which combines in a peculiar manner with other sub-
stances, and brings them into a semi-fluid state of aggrega-
tion. We can therefore, from these general outlines of the
inorganic history of the earth's crust, deduce the important
fact, that at a certain definite time life had its beginning on
earth, and that terrestrial organisms did not exist from
eternity, but at a certain period came into existence for the
first time.

Now, how are we to conceive of this origin of the first
organisms ? This is the point at which most naturalists,
even at the present day, are inclined to give up the attempt
at natural explanation, and take refuge in the miracle of an
inconceivable creation. In doing so, as has already been re-
marked, they quit the domain of scientific knowledge, and
renounce all further insight into the eternal laws which have
determined nature's history. But before despondingly taking
such a step, and before we despair of the possibility of
any knowledge of tliis important process, we may at least
make an attempt to understand it. Let us see if in reality
the origin of a first organism out of inorganic matter, the
origin of a living body out of lifeless matter, is so utterly
inconceivable and beyond all experience. In one word, let
us examine the question of spontaneous generation, or archi-
gony. In so doing, it is above aU things necessary to form
a clear idea of the principal properties of the two chief

328 THE HISTORY OF CREATION.

groups of natural bodies, the so-called inanimate or inor-
ganic, and the animate or organic bodies, and then estab-
lish what is common to, and what are the differences be-
tween, the two groups. It is desirable to go somewhat care-
fully into the comiDarison of organisms and anorgana,
since it is commonly very much neglected, although it is
necessary for a right understanding of nature from the
monistic point of view. It will be most advantageous here
to look separately at the three fundamental properties of
every natural body ; these are matter, form, and force. Let
us begin with 7)iatter. (Gen. Morph. iii.)

By chemistry we have succeeded in analysing all bodies
known to us into a small number of elements or simple sub-
stances, which cannot be further divided, for example,
carbon, oxygen, nitrogen, sulphur, and the different metals :
potassium, sodium, iron, gold, etc. At present we know
about seventy such elements or simple substances. The
majority of them are unimportant and rare ; the minority
only are widely distributed, and compose not only most of
the anorgana, but also all organisms. If we compare those
elements which constitute the body of organisms with those
which are met with in anorgana, we have first to note the
highly important fact that in animal and vegetable bodies
no element occurs but what can be found outside of them in
inanimate nature. There are no special organic elements or
simple organic substances.

The chemical and physical differences existing between
organisms and anorgana, consequently, do not lie in their
material foundation; they do not arise from the different
nature of the elements composing them, but from the dif-
ferent manner in which the latter are united by chemical

PECULIAR STATE OF LIVING MATTER. 329

combination. This different manner of combination gives
rise to certain physical peculiarities, especially in density of
substance, which at first sight seems to constitute a deep
chasm between the two groups of bodies. Inorganic or
inanimate natural bodies, such as crystals and the amorphous
rocks, are in a state of density which we call the firm or
solid state, and which we oppose to the liquid state of water
and to the gaseous state of air. It is familiar to every one
that these three difierent degrees of density, or states of
aggregation of anorgana, are by no means peculiar to the
different elements, but are the results of a certain degTee
of temperature. Every inorganic solid body, by increase of
temperature, can be reduced to the liquid or melted state,
and, by further heat, to the gaseous or elastic state. In the
same way most gaseous bodies, by a proper decrease of
temperature can first be converted into a liquid state, and
further, into a solid state of density.

In opposition to these three states of density of anorgana,
the living body of aU organisms — animals as weU as plants
— is in an altogether peculiar fourth state of aggregation.
It is neither solid like stone, nor liquid like water, but pre-
sents rather a medium between these two states, which may
therefore be designated as the firm-fluid or swollen state of
aggregation (viscid). In all living bodies, without exception,
there is a certain quantity of water combined in a peculiar
way with sohd matter, and owing to this characteristic
combination of water with solid matter we have that
soft state of aggregation, neither solid nor liquid, which
is of great importance in the mechanical explanation of
the phenomena of life. Its cause lies essentially in the
physical and chemical properties of a simple, indivisible,

330 THE HISTORY OF CREATION.

elementary substance, namely, carhon (Gen. Morph. i.
122-180).

Of all elements, carbon is to us by far the most important
and interesting, because this simple substance play^ the
largest part in all animal and vegetable bodies known to
us. It is that element which, by its peculiar tendency to
form complicated combinations with the other elements,
produces the greatest variety of chemical compounds, and
among them the forms and living substance of animal and
vegetable bodies. Carbon is especially distinguished by
the fact that it can unite with the other elements in
infinitely manifold relations of number and weight. By the
combination of carbon with three other elements, with
oxygen, hydrogen, and nitrogen (to which generally sulphur,
and frequently, also, phosphorus is added), there arise those
exceedingly important compounds which we have become
acquainted with as the first and most indispensable
substratum of all vital phenomena, the albuminous combina-
tions, or albuminous bodies (protean matter).

We have before this (p. 185) become acquainted with the
simplest of all species of organisms in the Monera, whose
entire bodies when completely developed consist of nothing
but a semi-fluid albuminous lump ; they are organisms which
are of the utmost importance for the theory of the first
origin of life. But most other organisms, also, at a certain
period of their existence — at least, in the first period of their
life — in the shape of egg-cells or germ-cells, are essentially
nothing but simple little lumps of such albuminous forma-
tive matter, known as plasma, or protoplasma. They then
differ from the Monera only by the fact that in the interior
of the albuminous corpuscle the cell-kernel, or nucleus, has

PEOTOPLASM, THE SEAT OF LIFE. 33 1

separated itself from the surrounding cell-substance (proto-
plasma). As we have already pointed out, the cells, with
their simple attributes, are so many citizens, who by
co-operation and differentiation build up the body of even
the most perfect organism ; this being, as it were, a cell
republic (p. 301). The fully developed form and the vital
phenomena of such an organism are determined solely by the
activities of these small albuminous corpuscles.

It may be considered as one of the greatest triumphs o:
recent biology, especially of the theory of tissues, that we
are now able to trace the wonder of the phenomena of life
to these substances, and that we can demonstrate the
infinitely manifold and complicated physical and chemical
properties of the albuminous bodies to he the real cause of
organic or vital phenomena. All the different forms of
organisms are simply and directly the result of the combi-
nation of the different forms of cells. The infinitely
manifold varieties of form, size, and combination of the cells
have arisen only gradually by the division of labour, and by
the gradual adaptation of the simple homogeneous lumps of
plasma, which originally were the only constituents of the
cell-mass. From this it follows of necessity that the
fundamental phenomena of life — nutrition and generation —
in their highest manifestations, as well as in their simplest
expressions, must also be traced to the material nature of
that albuminous formative substance. The other vital
activities are gradually evolved from these two. Thus,
then, the general explanation of life is now no more
difficult to us than the explanation of the physical properties
of inorganic bodies. All vital phenomena and formative
processes of organisms are as directly dependent upon the

33^ THE HISTORY OF CEEATTON.

chemical composition and the physical forces of organic
matter as the vital phenomena of inorganic crystals — that is,
ihe process of their growth and their specific formation — are
the direct results of their chemical composition and of their
physical condition. The ultimate causes, it is true, remain
in both cases concealed from us. When gold and copper
crystallize in a cubical, bismuth and antimony in a
hexagonal, iodine and sulphur in a rhombic form of
crystal, the occurrence is in reality neither more nor less
mysterious to us than is every elementary process of
organic formation, every self-formation of the organic cell.
In this respect we can no longer draw a fundamental
distinction between organisms and anorgana, a distinction
of which, formerly, naturalists were generally convinced.

Let us secondly examine the agreements and differences
which are presented to us in the formation of organic and
inorganic natural bodies (Gen. Morph. i. 130). Formerly
the simple structure of the latter and the composite
structure of the former were looked upon as the principal
distinction. The body of all organisms was supposed to
consist of dissimilar or heterogeneous parts, of instruments
or organs which worked together for the purposes of life.
On the other hand, the most perfect anorgana, that is to say,
crystals, were supposed to consist entirely of continuous or
homogeneous matter. This distinction appears very essen-
tial But it loses aU importance through the fact that in
late years we have become acquainted with the exceedingly
remarkable and important Monera.^^ (Compare above,
p. 185). The whole body of these most simple of all
organisms — a semi-fluid, formless, and simple lump of
albumen — consists, in fact, of only a single chemical combi-

FUNDAMENTAL FOP.MS. 333

nation, and is as perfectly simple in its structure as any
crystal, which consists of a single inorganic combination,
for example, of a metallic salt or of a silicate of the earths
and alkalies.

As naturalists believed in differences in the inner struc-
ture or composition, so they supposed themselves able to
find complete differences in the external forms of organisms
and anorgana, especially in the mathematically determinable
crystalline forms of the latter. Certainly crystallization
is pre-eminently a quality of the so-called anorgana.
Crystals are Hmited by plane surfaces, which meet in
straight lines and at certain measurable angles. Animal
and vegetable forms, on the contrary, seem at first sight to
admit of no such geometrical determination. They are for
the most part limited by curved surfaces and crooked lines,
which meet at variable angles. But in recent times we
have become acquainted, among Radiolaria ^^ and among
many other Protista, with a large number of lower
organisms, whose body, in the same way as crystals, may be
traced to a mathematically determinable fundamental form,
and whose form in its whole, as well as in its parts, is
bounded by definite geometrically determinable planes and
angles. In my general doctrine of Fundamental Forms, or
Promorphology, I have given detailed proofs of this, and at
the same time established a general system of forms, the ideal
stereometrical type-forms, which explain the real forms of
inorganic crystals, as well as of organic individuals (Gen.
Morph. i. 375-574). Moreover, there are also perfectly
amorphous organisms, like the Monera, Amoeba, etc., which
change their forms every moment, and in which we are as
little able to point out a definite fundamental form as in

334 THE HISTORY OF CREATION.

the case of the shapeless or amorphous anorgana, such as
non-crystallized stones, deposits, etc. We are consequently
unable to find any essential difference in the external
forms or the inner structure of anoro-ana and orojanisms.

Thirdly, let us turn to the forces or the pJienoonena of
viotion of these two different groups of bodies (Gen. Morph.
i. 140). Here we meet with the greatest difficulties. The
vital phenomena, known as a rule only in the highly
developed organisms, in the more perfect animals and plants,
seem there so mysterious, so wonderful, so peculiar, that
most persons are decidedly of opinion that in inorganic
nature there occurs nothing at all similar, or in the least
degree comparable to them. Organisms are for this very
reason called animate, and the anorgana, inanimate natural
bodies. Hence, even so late as the commencement of the
present century, the science which investigates the
phenomena of life, namely physiology, retained the
erroneous idea that the physical and chemical properties
of matter were not sufficient for explaining these
phenomena. In our own day, especially during the last
ten years, this idea may be regarded as having been com-
pletely refuted. In physiology, at least, it has now no
place. It now never occurs to a physiologist to consider
any of the vital phenomena as the result of a mysterious
vital force, of an active power working for a definite purpose,
standing outside of matter, and, so to speak, taking only
the physico-chemical forces into its service. Modern
physiology has arrived at the strictly monistic conviction
that all of the vital phenomena, and, above all, the two
fundamental phenomena of nutrition and propagation are
purely physico-chemical processes, and directly dependent

THE CARBON THEORY. 335

on the material nature of the organism, just as all the
physical and chemical qualities of every crystal are
determined solely by its material composition. Now, as
the elementary substance which determines the peculiar
material composition of organisms is carbon, we nmst
ultimately reduce all vital phenomena, and, above all, the
two fundamental phenomena of nutrition and propagation
to the properties of the carbon. The peculiar-chemico-
physical properties, and especially the semi-Jiuid state oj
aggregation, and the easy decomposihility of the exceedingly
composite albuminous combinations of carbon, are the
m^echanical causes of those peculiar phenomena of motion
which distinguish organisms from anorgana, and luhich
in a narrow sense are usually called " life!'

In order to understand this " carbon theory',' which I have
established in detail in the second book of my General
Morphology, it is necessary, above all things, closely to
examine those phenomena of motion which are common to
both groups of natural bodies. First among them is the
process of growth. If we cause any inorganic solution of
salt slowly to evaporate, crystals are formed in it, which
slowly increase in size during the continued evaporation of
the water. This process of growth arises from the fact
that new particles continually pass over from the fluid state
of aggregation into the solid, and, according to certain laws,
deposit themselves upon the firm kernel of the crystal
already formed. From such an apposition of particles arise
the mathematically definite crystalline shapes. In like
manner the growth of organisms takes place by the accession
of new particles. The only difference is that in the growth
of organisms, in consequence of their semi-fiuid state of

33^ THE HISTORY OF CREATION.

aggregation, the newly-added particles penetrate into the
interior of the organism (inter-susception), whereas anor-
gana receive homogeneous matter from without only by
apposition or an addition of new particles to the surface.
This important difference of gi^owth by inter-susception
and by apposition is obviously only the necessary and direct
result of the different conditions of density or state of
ao^o^reo^ation in oro^anisms and anorgana.

Unfortunately I cannot here follow in detail the various
exceedingly interesting parallels and analogies which occur
between the formation of the most perfect anorgana, the
crystals, and the formation of the simplest organisms, the
Monera and their next kindred forms. For this I must
refer to a minute comparison of organisms and anorgana,
which I have carried out in the fifth chapter of my General
Morphology (Gen. Morph. i. 111-160). I have there
shown in detail that there exist no complete differences
between organic and inorganic natural bodies, neither in
respect to form and structure, nor in respect to matter and
force ; and that the actually existing differences are dependent
upon the peculiar nature of the carbon; and that there
exists no insurmountable chasm between organic and
inorganic nature. We can perceive this most important
fact very clearly if we examine and compare the origin of
the forms in crystals and in the simplest organic individuals.
In the formation of crystal individuals, two different counter-
acting formative tendencies come into operation. The inner
constructive force, or the inner formative tendency, which
corresponds to the Heredity of organisms, in the case of the
crystal is the direct result of its material constitution or of
its chemical composition. The form of the crystal, so far as

ADAPTATION IN CRYSTALS. 337

it is determined by this inner original formative tendency,
is the result of the specific and definite way in which the
smallest particles of the crystallizing matter unite together
in different directions according to law. That independent
inner formative force, which is directly inherent in the
matter itself, is directly counteracted by a second formative
force. The external constructive force, or the external
formative tendency, may be called Adaptation in crystals as
well as in organisms. Every crystal individual during its
formation, like every organic individual, must submit and
adapt itself to the surrounding influences and conditions
of existence of the outer world. In fact, the form and size of
every crystal is dependent upon its whole surroundings, for
example, upon the vessel in which the crystallization takes
place, upon the temperature and the pressure of the air
under which the crystal is formed, upon the presence or
absence of heterogeneous bodies, etc. Consequently, the
form of every single crystal, like the form of every single
organism, is the result of the interaction of two opposing
factors — the inner formative tendency, which is determined
by the chemical constitution of the matter itself, and of the
external formative tendency, which is dependent upon the
influence of surrounding matter. Both these constructive
forces interact similarly also in the organism, and, just as in
the crystal, are of a purely mechanical nature and directly
inherent in the substance of the body. If we designate the
growth and the formation of organisms as a process of life, we
may with equal reason apply the same term to the developing
crystal. The teleological conception of nature, which looks
upon organisms as machines of creation arranged for a
definite purpose, must logically acknowledge the same also

33^ THE HISTORY OF CEEATION.

in regard to the forms of crystals. The differences which
exist between the simplest organic individuals and inorganic
crystals are determined by the solid state of aggregation of
the latter, and by the semi-fluid state of the former.
Beyond that the causes producing form are exactly the
same in both. This conviction forces itself upon us most
clearly, if we compare the exceedingly remarkable pheno-
mena of growth, adaptation, and the " correlation of parts "
of developing crystals with the corresponding phenomena
of the origin of the simplest organic individuals (Monera
and cells). The analogy between the two is so great that,
in reality, no accurate boundary can be drawn. In my
General Morphology I have quoted in support of this a
number of striking facts (Gen. Morph. i. 14(j, 156, 158.)

If we vividly picture to ourselves this "unity of
organic and inorganic nature^,' this essential agreement of
organisms and anorgana in matter, form, and force, and if
we bear in mind that we are not able to establish any
one fundamental distinction between these two groups of
bodies (as was formerly generally assumed), then the ques-
tion of spontaneous generation will lose a great deal of the
difficulty which at first seems to surround it. Then the
development of the first organism out of inorganic matter
will appear a much more easily conceivable and intelligible
process than has hitherto been the case, whilst an artificial
absolute barrier between organic or animate, and inorganic
or inanimate nature was maintained.

In the question of spontaneous generation, or archigony,
which we can now answer more definitely, it must be borne
in mind that by this conception we understand generally
the non-parental generation of an organic individual, the

AUTOGENY AND PLASMOGENY. 339

origin of an organism independent of a parental or pro-
ducing organism. It is in this sense that on a former
occasion (p. 183) I mentioned spontaneous generation
(archigony) as opposed to parental generation or propaga-
tion (tocogony). In the latter case the organic individual
arises by a greater or less portion of an already existing
organism separating itself and growing independently.
(Gen. Morph. ii. 32.)

In spontaneous generation, which is often also called
original generation (generatio spontanea, sequivoca, primaria
etc,) we must first distinguish two essentially difierent
kinds, namely, autogeny and plasmogeny. By autogeny
we understand the origin of a most simple organic indi-
vidual in an inorganic formative fluid, that is, in a
fluid which contains the fundamental substances for the
composition of the organism dissolved in simple and loose
combinations (for example, carbonic acid, ammonia, binary
salts, etc.). On the other hand, we call spontaneous genera-
tion plasmogeny when the organism arises in an organic
formative fluid, that is, in a fluid which contains those
requisite fundamental substances dissolved in the form of
complicated and fluid combinations of carbon (for example,
albumen, fat, hydrate of carbon, etc.). (Gen. Morph. i. 174.
ii 33.)

Neither the process of autogeny, nor that of plasmogeny,
has yet been directly observed with perfect certainty.
In early, and also in more recent times, numerous and
interesting experiments have been made as to the possibility
or reality of spontaneous generation. Almost all these
experiments refer not to autogeny, but to plasmogeny, to the
origin of an organism out of already formed organic matter.

340 THE HISTORY OF CREATION.

It is evident, however, that this latter process is only of
subordinate interest for our history of creation. It is much
more important for us to solve the question, " Is there such,
a thing as autogeny ? Is it possible that an organism can
arise, not out of pre-existing organic, but out of purely inor-
ganic, matter ? " Hence we can quietly lay aside all the
numerous experiments which refer only to plasmogeny,
which have been carried on very zealously during the last
ten years, and which for the most part have had a negative
result. For even supposing that the reality of plasmogeny
were strictly proved, still autogeny would not be explained
by it.

The experiments on autogeny have likewise as yet
furnished no certain and positive result. Yet we must at
the outset most distinctly protest against the notion
that these experiments have proved the impossibility of
spontaneous generation in general. Most naturalists who
have endeavoured to decide this question experimentally,
and who, after having employed all possible precautionary
measures, under well-ascertained conditions, have seen no
organisms come into being, have straightway made the
assertion, on the ground of these negative results : " That it
is altogether impossible for organisms to come into existence
by themselves without parental generation." This hasty
and inconsiderate assertion they have supported by the
negative results of their experiments, which, after all, could
prove nothing except that, under these or those highly
artificial circumstances created by the experimenters them-
selves, no organism was developed. From these experi-
ments, which have been for the most part made under the
most unnatural conditions, and in a highly artificial

PRIMEVAL CONDITIONS DIFFEHED. 347

manner, we can by no means draw the conclusion that
spontaneous ^generation in general is impossible. The
impossibility of such a process can, in fact, never be proved.
For how can we know that in remote primaeval times there
did not exist conditions quite different from those at
present obtaining, and which may have rendered spon-
taneous generation possible ? Indeed, we can even positively
and with full asssurance maintain that the general
conditions of life in primaeval times must have been entirely
different from those of the present time. Think only of the
fact that the enormous masses of carbon which we now
find deposited in the primary coal mountains were first
reduced to a solid form by the action of vegetable life, and
are the compressed and condensed remains of innumerable
vegetable substances, which have accumulated in the course
of many millions of years. But at the time when, after
the origin of water in a liquid state on the cooled
crust of the earth, organisms were first formed by
spontaneous generation, those immeasurable quantities of
carbon existed in a totally different form, probably for the
most part dispersed in the atmosphere in the shape of
carbonic acid. The whole composition of the atmosj)here
was therefore extremely different from the present.
Further, as may be inferred upon chemical, physical, and
geological grounds, the density and the electrical conditions
of the atmosphere were quite different. In like manner the
chemical and physical nature of the primaeval ocean, which
then continuously covered the whole surface of the earth as
an uninterrupted watery sheet, was quite peculiar. Tht,*
temperature, the density, the amount of salt, etc., must have

been very different from those of the present ocean. In
16

342 THE HISTORY OF CREATION.

any case, therefore, even if we do not know anything more
about it, there remains to us the supposition, "which can at
least not be disputed, that at that time, under conditions
quite different from those of to-day, a spontaneous genera-
tion, which now is perhaps no longer possible, may have
taken place.

But it is necessary to add here that, by the recent pro-
gress of chemistry and physiology, the mysterious and
miraculous character which at first seems to belong to this
much disputed and yet inevitable process of spontaneous
generation, has been to a great extent, or almost entirely,
destroyed. Not fifty years ago, all chemists maintained that
we were unable to produce artificially in our laboratories
any complicated combination of carbon, or so-called "organic
combination." The mystic " vital force " alone was sup-
posed to be able to produce these combinations. When,
therefore, in 1828, Wohler, in Gottingen, for the first time
refuted this dogma, and exliibited pure " organic " urea, ob-
tained in an artificial manner from a purely inorganic body
(cyanate of ammonium), it caused the greatest surprise and
astonishment. In more recent times, by the progress of syn-
thetic chemistry, we have succeeded in producing in our
laboratories a great variety of similar " organic " combin-
ations of carbon, by purely artificial means — for example
alcohol, acetic acid, formic acid. Indeed, many exceed-
ingly complicated combinations of carbon are now arti-
ficially produced, so that there is every likelihood, sooner
or later, of our producing artificially the most complicated,
and at the same time the most important of all, namely, the
albuminous combinations, or plasma-bodies. By the con-
sideration of this probability, the deep chasm which was

THE MONERA AND ARCHIGONY. 343

formerly and generally believed to exist between organic
and inorganic bodies is almost or entirely removed, and the
way is paved for the conception of spontaneous generation.

Of still greater, nay, the very greatest importance to the
hypothesis of spontaneous generation are, finally, the exceed-
ingly remarkable Monera, those creatures which we have
already so frequently mentioned, and which are not only the
simplest of all observed organisms, but even the simplest of
all imaginable organisms. I have already described these
wonderful "organisms without organs," when examining
the simplest phenomena of propagation and inheritance.
We already know seven different genera of these Monera,
some of which live in fresh water, others in the sea (com-
pare above, p. 184 ; also Plate I. and its explanation
in the Appendix). In a perfectly developed and freely
motile state, they one and aU present us with nothing but a
simple little lump of an albuminous combination of carbon.
The individual genera and species differ only a little in the
manner of propagation and development, and in the way of
taking nourishment. Through the discovery of these organ-
isms, which are of the utmost importance, the supposition
of a spontaneous generation loses most of its difficulties.
For as all trace of organization — all distinction of hetero-
geneous parts — is still wanting in them, and as all the vital
phenomena are performed by one and the same homogeneous
and formless matter, we can easily imagine their origin by
spontaneous generation. If this happens through plas-
riiogeny, and if plasma capable of life already exists, it
then only needs to individualize itself in the same way as
the mother liquor of crystals individualizes itself in crys-
tallization. If, on the other hand, the spontaneous generation

344 THE HISTOKY OF CKEATION.

of the Monera takes place by true autogeny, then it is
further requisite that that plasma capable of life, that pri-
maeval mucus, should be formed out of simpler combinations
of carbon. As we are now able artificially to produce,
in our laboratories, combinations of carbon similar to this
in the complexity of their constitution, there is absolutely
no reason for supposing that there are not conditions in free
nature also, in which such combinations could take place.
Formerly, when the doctrine of spontaneous generation was
advocated, it failed at once to obtain adherents on account
of the composite structure of the simplest organisms then
known. It is only since we have discovered the exceedingly
important Monera, only since we have become acquainted
in them with organisms not in any way built up of distinct
organs, but which consist solely of a single chemical combin-
ation, and yet grow, nourish, and propagate themselves, that
this great difficulty has been removed, and the hypothesis of
spontaneous generation has gained a degree of probabiHty
which entitles it to fill up the gap existing between Kant's
cosmogony and Lamarck's Theory of Descent. Even
among the Monera at present known there is a species
which probably, even now, always comes into existence by
spontaneous generation. This is the wonderful Bathyhius
Hceckelii, discovered and described by Huxley. As I have
already mentioned (p. 184), this Moneron is found in the
greatest depths of the sea, at a depth of between 12,000 and
24,000 feet, where it covers the ground partly as retiform
threads and plaits of plasma, partly in the form of larger or
smaller irregular lumps of the same material.*

* We must wait for fuller information on the subject of Bathybius, at the
hands of the naturalists of the Challenger expedition, before accepting
it finally as a distinct organism. — Editor.

THE MONERON BECOMES A CELL. 345

Only such homogeneous organisms as are yet not
differentiated, and are similar to inorganic crystals in
being homogeneously composed of one single substance,
could arise by spontaneous generation, and could become the
primaeval parents of all other organisms. In their further
development we have pointed out that the most important
process is the formation of a kernel or nucleus in the simple
little lump of albumen. We can conceive this to take place
in a purely physical manner, by the condensation of the
innermost central part of the albumen. The more solid
central mass, which at first gradually shaded ofl* into the
peripheral plasma, becomes sharply separated from it, and
thus forms an independent, round, albuminous corpuscle,
the kernel ; and by this process the Moneron becomes
a cell. Now, it must have become evident from our
previous chapters, that the further development of all
other organisms out of such a cell presents no difficulty, for
every animal and every plant, in the beginning of its indi-
vidual life, is a simple cell. Man, as well as every other
animal, is at first nothing but a simple «gg-cell, a single
lump of mucus, containing a kernel (p. 297, Fig. 5).

In the same way as the kernel of the organic cell
arose in the interior or central mass of the originally homo-
geneous lump of plasma, by separation, so, too, the first cell-
Tnembrane was formed on its surface. This simple, but most
important process, as has already been remarked, can like-
wise be explained in a purely physical manner, either as a
chemical deposit, or as a physical condensation in the upper-
most stratum of the mass, or as a secretion. One of the first
processes of adaptation effected by the Moneron originating
by spontaneous generation must have been the condensation

34^ THE HISTORY OF CREATION.

of an external crust, which as a protecting covering shut in
the softer interior from the hostile influences of the
outer world. As soon as, by condensation of the homo-
geneous Moneron, a cell-kernel arose in the interior and
a membrane arose on the surface, all the fundamental
parts of the unit were furnished, out of which, by infinitely
manifold repetition and combination, as attested by actual
observation, the body of higher organisms is constructed.

As has already been mentioned, our whole understanding
of an organism rests upon the cell theory established thirty
years ago by Schleiden and Schwann. According to it,
every organism is either a simple cell or a cell-community,
a republic of closely connected cells. All the forms and
vital phenomena of every organism are the collective result
of the forms and vital phenomena of all the single cells of
which it is composed. By the recent progTess of the cell
theory it has become necessary to give the elementary
organisms, that is, the " organic " individuals of the first
order, which are usually designated as cells, the more
general and more suitable name of form-units, or plastids,
Among these form-units we distinguish two main groups,
namely, the cytods and the genuine cells. The cytods are,
like the Monera, pieces of plasma without a kernel
(p. 186, Fig. 1). Cells, on the other hand, are pieces of plasma
containing a kernel or nucleus (p. 188, Fig. 2). Each of
these two main groups of plastids is again divided into two
subordinate groups, according as they possess or do not
possess an external covering (skin, shell, or membrane).
We may accordingly distinguish the following foui* grades
or species of plastids, namely: 1. Sionple cytods (p. 186.
Fig. 1 A) ; 2. Encased cytods; 3. Simple cells (p. 188;

FOUR OEDERS OF PLASTIDS. 347

Fig. 2B)\ 4. Encased cells (p. 188, Fig. 2 A). (Gen. Morpli.
I 269-289.)

Concerning the relation of these four forms of plastids
to spontaneous generation, the following is the most
probable : — 1. The simple cytocls (Gymnocytoda), naked
particles of plasma without kernel, like the still living
Monera, are the only plastids which directly come into
existence by spontaneous generation, 2. The enclosed cytods
(Lepocytoda), particles of plasma without kernel, which are
surrounded by a covering (membrane or shell), arose out of
the simple cytods either by the condensation of the outer
layers of plasma or by the secretion of a covering. 3. The
simple cells (Gymnocyta), or naked cells, particles of plasma
with kernel, but without covering, arose out of the simple
cytods by the condensation of the innermost particles of
plasma into a kernel, or nucleus, by differentiation of a
central kernel and peripheral cell-substance. 4. The
enclosed cells (Lepocyta), or testaceous cells, particles of
plasma with kernel and an outer covering (membrane or
shell), arose either out of the enclosed cytods by the forma-
tion of a kernel, or out of the simple cells by the formation
of a membrane. All the other forms of form-units, or
plastids, met with, besides these, have only subsequently
arisen out of these four fundamental forms by natural
selection, by descent with adaptation, by differentiation
and transformation.

By this theory of plastids, by deducing all the different
forms of plastids, and hence, also, all organisms composed
of them, from the Monera, we obtain a simple and natural
connection in the whole series of the development of nature.
The origin of the first Monera by spontaneous generation

34^ THE HISTORY OF CREATION".

appears to us as a simple and necessary event in the pro-
cess of the development of the earth. We admit that this
process, as long as it is not directly observed or repeated by
experiment, remains a pure hypothesis. But I must again
say that this hypothesis is indispensable for the consistent
completion of the non-miraculous history of creation, that
it has absolutely nothing forced or miraculous about it,
and that certainly it can never be positively refuted. It
must be taken into consideration that the process of spon-
taneous generation, even if it still took place daily and
hourly, would in any case be exceedingly difficult to observe
and establish with absolute certainty as such. With regard
to the Monera, we find ourselves placed before the following
alternative : either they are actually directly derived from
pre-existing, or " created," most ancient Monera, and in this
case they would have had to propagate themselves un-
changed for many millions of years, and to have maintained
their original form of simple particles of plasma ; or, the
"present Monera have originated much later in the course of
the organic history of the earth, by repeated acts of spon-
taneous generation, and in this case spontaneous generation
may take place now as well as then. The latter suppo-
sition has evidently much more probability on its side than
the former.

If we do not accept the hjrpothesis of spontaneous
generation, then at this one point of the history of develop-
ment we must have recourse to the miracle of a super-
natural creation. The Creator must have created the first
organism, or a few first organisms, from which all others are
derived, and as such he must have created the simjDlest
Monera, or primseval cytods, and given them the capability

CONTINUITY OF NATURE. 349

of developing further in a mechanical way. I leave it to
each one of my readers to choose between this idea and the
hypothesis of spontaneous generation. To me the idea that
the Creator should have in this one point arbitrarily inter-
fered with the regular process of development of matter,
which in all other cases proceeds entirely without his inter-
position, seems to be just as unsatisfactory to a believing
mind as to a scientific intellect. If, on the other hand,
we assume the hypothesis of spontaneous generation for the
origin of the first organisms, which in consequence of
reasons mentioned above, and especially in consequence of
the discovery of the Monera, has lost its former difficulty,
then we arrive at the establishment of an uninterrupted
natural connection between the development of the earth
and the organisms produced on it, and, in this last remain-
ing lurking-place of obscurity, we can proclaim the unity
of all Nature, and the unity of her laws of Develo'jpment
(Gen. Morph. 1 164).

350 THE HISTORY OF CHEATION.

CHAPTER Xiy.

MIGRATIOTT AND DISTRIBUTION OF ORGANISMS.
CHOROLOGY AND THE ICE-PERIOD OF THE EARTH.

Chorological Facts and Canses. — Origin of most Species in one Single
Locality : " Centres of Creation." — Distribution by Migration. — Active
and Passive Migrations of Animals and Plants. — Means of Transport. —
Transport of Germs by "Water and by Wind. — Continual Change of the
Area of Distribution by Elevations and Depressions of the Ground. —
Chorological Importance of Geological Processes. — Influence of the
Change of Climate. — Ice or Glacial Period. — Its Importance to
Chorology. — Importance of Migrations for the Origin of New Species.
— Isolation of Colonists. — ^Wagner's Law of Migration. — Connection
between the Theory of Migration and the Theory of Selection. — Agree-
ment of its Results with the Theory of Descent.

As I have repeatedly said, but cannot too much emphasize,
the actual value and invincible strength of the Theory
of Descent does not lie in its explaining this or that single
phenomenon, but in the fact that it explains all biological
phenomena, that it makes all botanical and zoological
series of phenomena intelligible in their relations to one
another. Hence every thoughtful investigator is the more
firmly and deeply convinced of its truth the more he
advances from single biological observations to a general
view of the whole domain of animal and vegetable life.
Let us now, starting from this comprehensive point of view,
survey a biological domain, the varied and complicated

HUMBOLDT, DARWIN, AND WALLACE. 35 1

phenomena of which may be explained with remarkable
simplicity and clearness by the theory of selection. I
mean Chorology, or the theory of the local distribution of
organisms over the surface of the earth. By this I do
not only mean the geographical distribution of animal
and vegetable species over the different parts and provinces
of the earth, over continents and islands, seas, and rivers ;
but also their topographical distribution in a vertical
direction, their ascending to the heights of mountains, and
their descending into the depths of the ocean. (Gen.
Morph. ii. 286.)

The strange chorological series of phenomena which
show the horizontal distribution of organisms over parts of
the earth, and their vertical distribution in heights and
depths, have long since excited general interest. In recent
times Alexander Humboldt ^^ and Frederick Schouw have
especially discussed the geography of plants, and Berghaus
and Schmarda the geography of animals, on a large scale.
But although these and several other naturalists have in
many ways increased our knowledge of the distribution of
animal and vegetable forms, and laid open to us a new
domain of science, full of wonderful and interesting
phenomena, yet Chorology as a whole remained, as
far as their labours were concerned, only a desultory
knowledge of a mass of individual facts. It could not be
called a science as long as the causes for the explanation of
these facts were wanting. These causes were first disclosed
by the theory of selection and its doctrine of the migrations
of animal and vegetable species, and it is only since the
works of Darwin and Wallace that we have been able to
speak of an independent science of Chorology.

352 THE HISTORY OF CKEATION.

If all the phenomena of the geographical and topographi-
cal distribution of organisms are examined by themselves,
without considering the gradual development of species, and
if at the same time, following the customary superstition, the
individual species of animals and plants are considered
as forms independently created and independent of one
another, then there remains nothing for us to do but to gaze
at those phenomena as a confused collection of incompre-
hensible and inexplicable miracles. But as soon as we
leave this low stand-point, and rise to the height of the
theory of development, by means of the supposition of a
blood-relationship between the different species, then all
at once a clear light falls upon this strange series of
miracles, and we see that all chorological facts can
be understood quite simply and clearly by the supposition of
a common descent of the species, and their passive and
active migi^ations.

The most important principle from which we must start
in chorology, and of the truth of which we are convinced by
due examination of the theory of selection, is that, as a rule,
every animal and vegetable species has arisen only once in
the course of time and only in one place on the earth — its
so-called " centre of creation" — by natural selection. I share
this opinion of Darwin's unconditionally, in respect to the
great majority of higher and perfect organisms, and in
respect to most animals and plants in which the division of
labour, or differentiation of the cells and organs of which
they are composed, has attained a certain stage. For it
is quite incredible, or could at best only be an exceedingly
rare accident, that all the manifold and complicated circum-
stances— all the different conditions of the struggle for life,

CENTEES OF CKEATION. 353

which influence the origin of a new species by natural
selection — should have worked together in exactly the
same agreement and combination more than once in the
earth's history, or should have been active at the same time
at several different points of the earth's surface.

On the other hand, I consider it to be very probable that
certain exceedingly imperfect organisms of the simplest
structure, forms of species of an exceedingly indifferent
nature, as, for example, many single-celled Protista, but
especially the Monera, the simplest of them all, should have
several times or simultaneously arisen in their specific form
in several parts of the earth. For the few and very simple
conditions by which their specific form was changed in the
struggle for life may surely have often been repeated, in
the course of time, independently in difierent parts of
the earth. Further, those higher specific forms also, which
have not arisen by natural selection, but by hybridism (the
previously-mentioned hybrid species, pp. 147 and 275), may
have repeatedly arisen anew in different localities. As,
however, this proportionately small number of organisms
does not especially interest us here, we may, in respect
of chorology, leave them alone, and need only take
into consideration the distribution of the great majority
of animal and vegetable species in regard to which the
single origin of every species in a single locality, in its
so-called " central point of creation," can be considered as
tolerably certain.

Every animal and vegetable species from the beginning
of its existence has possessed the tendency to spread beyond
the limited locality of its origin, beyond the boundary of
its "centre of creation," or, in other words, beyond its

354 TS^ HISTORY OF CREATIOI^.

primcBval home, or its natal place. This is a necessary
consequence of the relations of population and over-popula-
tion (pp. 161 and 256). The more an animal or vegetable
species increases, the less is its limited natal place sufficient
for its sustenance, and the fiercer the struggle for life ; the
more rapid the over-population of the natal spot, the more
it leads to eTYiigration. These migrations are common to all
organisms, and are the real cause of the wide distribution
of the different species of organisms over the earth's surface.
Just as men leave over-crowded states, so all animals and
plants migrate from their over-crowded primaeval homes.

Many distinguished naturalists, especially LyelP^ and
Schleiden, have before this repeatedly drawn attention to
the great importance of these very interesting migrations of
organisms. The means of transport by which they are
effected are extremely varied. Darwin has discussed these
most excellently in the eleventh and twelfth chapters of
his work, which are exclusively devoted to " geographical
distribution," The means of transport are partly active,
partly passive; that is to say, the organism effects its
migration partly by free locomotion due to its own activity,
and partly by the movements of other natural bodies in
which it has no active share.

It is self-evident that active migrations play the chief
part in animals able to move freely The more freely an
animal's organization permits it to allmove in directions, the
more easily the animal species can migrate, and the more
rapidly it will spread over the earth. Flying animals are of
course most favoured in this respect, among vertebrate animals
especially birds, and among articulated animals, insects.
These two classes, as soon as they came into existence, can

MEANS OF MIGRATION. 355

have more easily spread over the whole earth than any other
animal, and this fact partly explains the extraordinary uni-
formity of structure which characterizes these two great
classes of animals. For, although they contain an ex-
ceedingly large number of different species, and although
the insect class alone is said to possess more different species
than all other classes of animals together, yet all the in-
numerable species of insects, and in like manner, also, the
different species of birds, agree most strikingly in all
essential peculiarities of their organization. Hence, in the
class of insects, as well as in that of birds, we can distinguish
only a very small number of large natural groups or orders,
and these few orders differ but very little from one another
in their internal structure. The orders of birds with their
numerous species are not nearly as distinct from one another
as the orders of the mammalian class, containing much fewer
species ; and the orders of insects, which are extremely rich
in genera and species, resemble one another much more
closely in their internal structure than do the much smaller
orders of the crab class. The general parallelism between
birds and insects is also very interesting in relation to syste-
matic zoology; and the great importance of their richness
in forms, for scientific morphology, lies in the fact that they
show us how, within the narrowest anatomical sphere, and
without profound changes of the essential internal organiz-
ation, the greatest variety in external bodily forms can be
attained. The reason of this is evidently their flying mode
of life and their free locomotion. In consequence of this
birds, as well as insects, have spread very rapidly over
the whole surface of the earth, have settled in aU possible
localities inaccessible to other animals, and variously modified

35^ THE HISTOKY OF CEEATION.

their specific form by superficial adaptation to particular
local relations.

Next to the flying animals, those animals, of course, have
spread most quickly and furthest which were next best able
to migrate, that is, the best runners among the inhabitants
of the land, and the best swimmers among the inhabitants of
the water. However, the power of such active migrations
is not confined to those animals which thi'oughout life enjoy
free locomotion. For the fixed animals also, such as corals,
tubicolous worms, sea-squirts, lily encrinites, sea-acorns, bar-
nacles, and many other lower animals which adhere to sea-
weeds, stones, etc., enjoy, at least at an early period of life,
free locomotion. They all migrate before they adhere to
anything. Their first free locomotive condition of early life
is generally that of a " ciliated " larva, a roundish, cellular
corpuscle, which, by means of a garb of movable " flimmer-
hairs," (Latin, " cilia ") swarms about in the water and bears
the name of Planula.

But the power of free locomotion, and hence, also, of active
migration, is not confined to animals alone, but many plants
likewise enjoy it. Many lower aquatic plants, especially the
class of the Tangles (Alg?e), swim about freely in the water
in early life, like the lower animals just mentioned, by
means of a vibratile hairy coat, a vibrating whip, or a
covering of tremulous fringes, and only at a later period
adhere to objects. Even in the case of many higher plants,
which we designate as creepers and climbing plants, we may
speak of active migration. Their elongated stalks and
perennial roots creep or climb during their long process
of growth to new positions, and by means of their wide-
spread branches they acquire new habitations, to which

PASSIVE MIGRATION. 357

they attach themselves by buds, and bring forth new
colonies of individuals of their species.

Influential as these active migrations of most animals
and many plants are, yet alone they would by no
means be sufficient to explain the chorology of organisms.
Passive Tnigrations have ever been by far the more import-
ant, and of far greater influence, in the case of most plants
and in that of many animals. Such passive changes of
locality are produced by extremely numerous causes. Air
and water in their eternal motion, wind and waves with
their manifold currents, play the chief part. The wind in
all places and at all times raises light organisms, small
animals and plants, but especially their young germs, animal
eggs and plant seeds, and carries them far over land and
seas. Where they fall into the water they are seized by
currents or waves and carried to other places. It is well
known, from numerous examples, how far in many cases
trunks of trees, hard shelled fruits, and other not readily
perishable portions of plants are carried away from their
original home by the course of rivers and by the currents
of the sea. Trunks of palm trees from the West Indies are
brought by the Gulf Stream to the British and Norwegian
coasts. All large rivers bring down driftwood from the
mountains, and frequently alpine plants are carried from their
home at the source of the river into the plains, and even
further, down to the sea. Frequently numerous inhabitants
live between the roots of the plants thus carried down, and
between the branches of the trees thus washed away there
are various inhabitants which have to take part in the
passive migration. The bark of the tree is covered with
mosses, lichens, and parasitic insects. Other insects, spiders,

358 THE HISTORY OF CREATION.

etc., even small reptiles and mammals, are hidden within
the hollow trunk or cling to the branches. In the earth
adhering to the fibres of the roots, in the dust lying in the
cracks of the bark, there are innumerable germs of smaller
animals and plants. Now, if the trunk thus washed away
lands safely on a foreign shore or on a distant island, the
guests who had to take part in the involuntary voyage can
leave their boat and settle in the new country. A very
remarkable kind of water-transport is formed by the floating
icebergs which annually become loosened from the eternal
ice of the Polar Sea. Although these cold regions are thinly
peopled, yet many of their inhabitants, who were accidentally
upon an iceberg while it was becoming loosened, are carried
away with it by the currents, and landed on warmer shores.
In this manner, by means of loosened blocks of ice from
the northern Polar Sea, often whole populations of small
animals and plants have been carried to the northern
shores of Europe and America. Nay, even polar foxes and
polar bears have been carried in this way to Iceland and to
the British Isles.

Transport by air is no less important than transport by
water in this matter of passive migration. The dust cover-
ing our streets and roofs, the earth lying on dry fields and
dried-up pools, the light moist soil of forests, in short, the
whole surface of the globe contains millions of small organ-
isms and their germs. Many of these small animals and
plants can without injury become completely dried up, and
awake again to life as soon as they are moistened. Every
o-ust of wind raises up with the dust innumerable little
creatures of this kind, and often carries them away to other
]ilaces miles off*. But even larger organisms, and especially

MODES OF MIGRATION. 359

their germs, may often make distant passive journeys througli
the air. The seeds of many plants are provided with light
feathery processes, which act as parachutes and facilitate their
flight in the air, and prevent their falling. Spiders make
journeys of many miles through the air on their fine fila-
ments, their so-called gossamer threads. Young frogs are
frequently raised by whirlwinds into the air by thousands,
and fall down in a distant part as a " shower of frogs." Storms
may carry birds and insects across half the earth's circum-
ference. They drop in the United States, having risen in
England. Starting from California, they only come to rest
in China. But, again, many other organisms may make the
journey from one continent to another together with the
birds and insects. Of course all parasites, the number of
which is legion, fleas, lice, mites, moulds, etc., migrate with
the organisms upon which they live. In the earth which
often remains sticking to the claws of birds there are also
small animals and plants or their germs. Thus the volun-
tary or involuntary migration of a single larger organism
may carry a whole small flora and fauna from one paii} of
the earth to another.

Besides the means of transport here mentioned, there
are many others which explain the distribution of animal
and vegetable species over the large tracts of the earth's
surface, and especially the general distribution of the so-
called cosmopolitan species. But these alone would not
nearly be sufficient to explain all chorological facts. How
is it, for example, that many inhabitants of fresh water
live in various rivers or lakes far away and quite apart from
one another ? How is it that many inhabitants of moun-
tains, which cannot exist in plains, are found upon entirely

2,6o THE HISTORY OF CREATION.

separated and far distant chains of mountains ? It is diffi-
cult to believe, and in many cases quite inconceivable, that
these inhabitants of fresh water should have in any way,
actively or passively, migrated over the land lying between
the lakes, or that the inhabitants of mountains in any
way, actively or passively, crossed the plains lying between
their mountain homes. But here geology comes to our help,
as a mighty ally, and completely solves these difficult pro-
blems for us.

The history of the earth's development shows us that the
distribution of land and water on its surface is ever and
continually changing. In consequence of geological changes
of the earth's crust, elevations and depressions of the ground
take place everywhere, sometimes more strongly marked in
one place, sometimes in another. Even if they happen so
slowly that in the course of centuries the seashore rises or
sinks only a few inches, or even only a few lines, still they
nevertheless effect great results in the course of long periods
of time. And long — immeasurably long — periods of time
have not been wanting in the earth's history. During the
course of many millions of years, ever since organic life ex-
isted on the earth, land and water have perpetually struggled
for supremacy. Continents and islands have sunk into the
sea, and new ones have arisen out of its bosom. Lakes and
seas have slowly been raised and dried up, and new water
basins have arisen by the sinking of the ground. Peninsulas
have become islands by the narrow neck of land which con-
nected them with the mainland sinking into the water.
The islands of an archipelago have become the peaks of a
continuous chain of mountains by the whole floor of their
sea being considerably raised.

CHANGES OF LAND AND WATER. 36 1

Thus the Mediterranean at one time was an inland sea,
when, in the place of the Straits of Gibraltar, an isthmus
connected Africa with Spain. England, even during the
more recent history of the earth, when man already
existed, has repeatedly been connected with the European
continent and been repeatedly separated from it. Nay,
even Europe and North America have been directly
connected. The South Sea at one time formed a
large Pacific Continent, and the numerous little islands
which now lie scattered in it were simply the highest
peaks of the mountains covering that continent. The
Indian Ocean formed a continent which extended from
the Sunda Islands along the southern coast of Asia to
the east coast of Africa. This large continent of former
times Sclater, an Englishman, has called Lemuria, from the
monkey-like animals which inhabited it, and it is at the
same time of great importance from being the probable
cradle of the human race, which in all likehhood here first
developed out of anthropoid apes. The important proof
which Alfred Wallace has furnished,^^ by the help of
chorological facts, that the present Malayan Archipelago
consists in reality of two completely different divisions,
is particularly interesting. Tlie western division, the Indo-
Malayan Archipelago, comprising the large islands of
Borneo, Java, and Sumatra, was formerly connected by
Malacca with the Asiatic continent, and probably also witli
the Lemurian continent just mentioned. The eastern
division, on the other hand, the Austro-Malayan Archipelago,
comprising Celebes, the Moluccas, New Guinea, Solomon's
Islands, etc., was formerly directly connected with Austra-
lia. Both divisions were formerly two continents separated

362 THE HISTORY OF CREATION.

hy a strait, but they have now for the most part sunk
below the level of the sea. Wallace, solely on the ground of
his accurate chorological observations, has been able in the
most acute manner to determine the position of this former
strait, the south end of which passes between Balij and
Lombok.

Thus, ever since liquid water existed on the earth, the
boundaries of water and land have eternally changed, and
we may assert that the outlines of continents and islands
have never remained for an hour, nay, even for a minute,
exactly the same. For the waves eternally and perpetually
break on the edge of the coast, and whatever the land in
these places loses in extent, it gains in other places by the
accumulation of mud, which condenses into solid stone and
ao-ain rises above the level of the sea as new land. Nothing^
can be more erroneous than the idea of a firm and
unchangeable outline of our continents, such as is im-
pressed upon us in early youth by defective lessons on
geography, which are devoid of a geological basis.

I need hardly draw attention to the fact that these
o-eoloo-ical chano-es of the earth's surface have ever been ex-
ceedingly important to the migrations of organisms, and
C(jnsequently to their Chorology. From them we learn to
understand how it is that the same or nearly related species of
animals and plants can occur on different islands, although
they could not have passed through the water separating
them, and how other species living in fresh water can inhabit
different enclosed water-basins, although they could not have
crossed the land lying between them. These islands were
formerly mountain peaks of a connected continent, and
these lakes were once directly connected with one another

PKIM^VAL CLIMATE OF THE EAETH. 36

'^

The former were separated by geological depressions
the latter by elevations. Now, if we further consider how
often and how unequally these alternating elevations and
depressions occur on the different parts of the earth, and how,
in consequence of this, the boundaries of the geographical
tracts of distribution of species become changed, and if
we further consider in what exceedingly various ways the
active and passive migrations of organisms must have been
influenced by them, then we shall be in a position to com-
pletely understand the great variety of the picture which
is at present offered to us by the distribution of animal
and vegetable species.

There is yet another important circumstance to be men-
tioned here, which is likewise of great importance for a
complete explanation of this varied geographical picture,
and which throws light upon many very obscure facts,
which, without its help, we should not be able to compre-
hend. I mean the gradual change of climate which has
taken place during the long course of the organic history of
the earth. As we saw in our last chapter, at the beginning
of organic life on the earth a much higher and more equal
temperature must have generally prevailed than at present.
The differences of zones, which in our time are so very
striking, did not exist at all in those times. It is probable
that for many millions of years but one climate prevailed
over the whole earth, which very closely resembled, or even
surpassed, the hottest tropical climate of the present day.
The highest north which man has yet reached was then
covered with palms and other tropical plants, the fossil re-
mains of which are still found there. The temperature of
tliis climate at a later period gradually decreased ; but still

364 THE HISTOEY OF CREATION.

the poles remained so warm that the whole surface of the
earth could be inhabited by organisms. It was only at a
comparatively very recent period of the earth's history,
namely, at the beginning of the tertiary period, that ther-j
occurred, as it seems, the first perceptible cooling of the
earth's crust at the poles, and through this the first differen-
tiation or separation of the different zones of temperature
or climatic zones. But the slow and gradual decrease or
temperature continued to extend more and more within the
tertiary period, until at last, at both poles of the earth, the
fir?5t permanent ice caps were formed.

I need scarcely point out in detail how very much this
change of climate must have affected the geographical dis-
tribution of organisms, and the origin of numerous new
species. The animal and vegetable species, which, down
to the tertiary period, had found an agreeable tropical
climate all over the earth, even as far as the poles,
were now forced either to adapt themselves to the in-
truding cold, or to flee from it. Those species which
adapted and accustomed themselves to the decreasing
temperature became new species simply by this very accli-
matization, under the influence of natural selection. The
other species, which fled from the cold, had to emigrate and
seek a milder climate in lower latitude-s. The tracts of dis-
tribution which had hitherto existed must by this have
been vastly changed.

However, during the last great period of the earth's
history, during the quaternary period (or diluvial period)
succeeding the tertiary one, the decrease of the heat
of the earth from the poles did not by any means remain
stationary. The temperature fell lower and lower, nay, even

THE GLACIAL PERIOD. 365

far below the present degree. Northern and Central Asia.
Europe, and North America from the north pole, were
covered to a great extent by a connected sheet of ice, which
in our part of the earth seems to have reached the Alps.
In a similar manner the cold also advancing from the south
pole covered a large portion of the southern hemisphere,
which is now free from it, with a rigid sheet of ice. Thus,
between these vast lifeless ice continents there remained
only a narrow zone to which the life of the organic world
had to withdraw. This period, during which man, or at
least the human ape, already existed, and which forms the
first period of the so-called diluvial epoch, is now universally
known as the ice or glacial period.

The ingenious Carl Schimper is the first naturalist who
clearly conceived the idea of the ice period, and proved the
great extent of the former glaciation of Central Europe by
the help of the so-called boulders, or erratic blocks of stone,
as also by the " glacier tables." Louis Agassiz, stimulated
by him, and considerably supported by the independent
investigations of the eminent geologist Charpentier, after-
wards undertook the task of carrying out the theory of the
ice period. In England, the geologist Forbes distinguished
himself in this matter, and also was the first to apply it
to the theory of migrations and the geographical distribu-
tion of species dependent upon migration. Agassiz, however,
afterwards injured the theory by his one-sided exaggeration,
inasmuch as, from his partiality to Cuvier's theory of cata-
clysms, he endeavoured to attribute the destruction of the
whole animate creation then existing, to the sudden coming
on of the cold of the ice period and the " revolution " con-
nected with it.
17

3(^^ THE HISTOKY OF CEEATION.

It is unnecessary here to enter into detail as to the ice
period itself, and into investigations about its limits, and
I may omit this all the more reasonably since the whole
of our recent geological hterature is full of it. It will be
found discussed in detail in the works of Cotta/^ Lyell,^^
Vogt,^^ Zittel,^^ etc. Its great importance to us here is
that it helps us to explain the most difficult chorological
problems, as Darwin has correctly perceived.

For there can be no doubt that this glaciation of the
present temperate zones must have exercised an exceedingly
important influence on the geogTaphical and topographical
distribution of organisms, and that it must have entirely
changed it. While the cold slowly advanced from the poles
towards the equator, and covered land and sea with a con-
nected sheet of ice, it must of course have driven the whole
living world before it. Animals and plants had to migrate
if they wished to escape being frozen. But as at that time
the temperate and tropical zones were probably no less
densely peopled with animals and plants than at present,
there must have arisen a fearful struggle for life between
the latter and the intruders coming from the poles. During
this struggle, which certainly lasted many thousands of
years, many species must have perished and many become
modified and been transformed into new species. The
hitherto existing tracts of distribution of species must have
become completely changed, and the struggle have been
continued, nay, indeed, must have broken out anew and
been carried on in new forms, when the ice period had
reached and gone beyond its furthest point, and when in
the post-glacial period the temperature again increased, and
organisms began to migrate back again towards the poles.

ALPINE AND ARCTIC SPECIES. 367

In any case this great change of climate, whether a
greater or less importance be ascribed to it, is one of
those occurrences in the history of the earth which have
most powerfully influenced the distribution of organic
forms. But more especially one important and difficult
chorological circumstance is explained by it in the simplest
manner, namely, the specific agTcement of many of our
Alpine inhabitants with some of those living in polar
regions. There is a great number of remarkable animal
and vegetable forms which are common to these two far
distant parts of the earth, and which are found nowhere
in the wide plains lying between them. Their migration
from the polar lands to the Alpine heights, or vice versa,
would be inconceivable under the present climatic circum-
stances, or could be assumed at least only in a few rare
instances. But such a migration could take place, nay,
was obliged to take place, during the gradual advance and
retreat of the ice-sheet. As the glaciation encroached from
Northern Europe towards our Alpine chains, the polar in-
habitants retreating before it — gentian, saxifrage, polar
foxes, and polar hares — must have peopled Germany, in
fact all Central Europe. When the temperature again in-
creased, only a portion of these Arctic inhabitants returned
with the retreating ice to the Arctic zones. Another portion
of them climbed up the mountains of the Alpine chain
instead, and there found the cold climate suited to them.
The problem is thus solved in a most simple manner.

We have hitherto principally considered the theory of the
tnigrations of organisms in so far as it explains the radiation
of every animal and vegetable species from a single pri-
maeval home, from a " central point of creation," and the

^68 THE HISTORY OF CREATION.

o

dispersion of these species over a greater or less portion of
the earth's surface. But these migrations are also of great
importance to the theory of development, because we can
perceive in them a very important means for the origin of
netu species. When animals and plants migrate they meet in
their new home, in the same way as do human emigrants,
with conditions which are more or less different from those
which they have inherited throughout generations, and to
which they have been accustomed. The emigrants must
either submit and adapt themselves to these new conditions
of life or they perish. By adaptation their peculiar specific
character becomes the more changed the greater the dif-
ference between the new and the old home. The new
climate, the new food, but above all, new neighbours in
the forms of other animals and plants, influence and tend
to modify the inherited character of the immigrant species,
and if it is not hardy enough to resist the influences, then
sooner or later a new species must arise out of it. In most
cases this transformation of an immigrant species takes
place so quickly under the influence of the altered struggle
for life, that even after a few generations a new species
arises from it.

Migration has an especial influence in this way on all
organisms with separate sexes. For in them the origin of
new species by natural selection is always rendered difficult,
or delayed, by the fact that the modified descendants oc-
casionally again mix sexually with the unchanged original
form, and thus by crossing return to the first form. But
if such varieties have migrated, if great distances or
barriers to migration — seas, mountains, etc. — have separated
them from the old home, then the danger of a mingling

INFLUENCE OF ISOLATION. 369

with the primary form is prevented, and the isolation of
the emigrant form, which becomes a new species by adapta-
tion, prevents its breeding with the old stock, and hence
prevents its return in this way to the original form.

The importance of migration for the isolation of newly-
originating species and the prevention of a speedy return to
the primary form has been especially pointed out by the
philosophic traveller, Moritz Wagner, of Munich. In a
special treatise on " Darwin's Theory and the Law of the
Migration of Organisms," ^^ Wagner gives from his own
rich experience a great number of striking examples which
confirm the theory of migration set forth by Darwin in
the eleventh and twelfth chapters of his book, where he es-
pecially discusses the effect of the complete isolation of emi-
grant organisms in the origin of new species. Wagner sets
forth the simple causes which have " locally bounded the
form and founded its typical difference," in the following
three propositions : — 1. The greater the total amount of
change in the hitherto existing conditions of life which the
emigrating individuals find on entering a new territory, the
more intensely must the innate variability of every organ-
ism manifest itself. 2. The less this increased individual
variability of organisms is disturbed in the peaceful process
of reproduction by the mingling of numerous subsequent
immigrants of the same species, the more frequently will
nature succeed, by intensification and transmission of the
new characteristics, in forming a new variety or race, that is,
a commencing species. 3. The more advantageous the
changes experienced by the individual organs are to the
variety, the more readily will it be able to adapt itself
to the surrounding conditions; and the longer the undis-

370 THE HISTORY OF CREATIOX.

turbed breeding of a commencing variety of colonists in a
new territory continues without its mingling with subse-
quent immigrants of the same species, the oftener a new
species will arise out of tlie variety."

Every one will agree with these three propositions of
Moritz Wagner's. But we must consider his view, that the
migration and the subsequent isolation of the emigrant in-
dividuals is a necessary condition for the origin of new
species, to be completely erroneous. Wagner says, " with
out a long-enduring separation of colonists from their former
species, the formation of a new race cannot succeed — selection,
in fact, cannot take place. Unlimited crossing, unliindered
sexual mingling of all individuals of a species will always
produce uniformity, and drive varieties, whose characteris-
tics have not been fixed throughout a series of generations,
back to the primary form."

This sentence, in which Wagner himself comprises the
main result of his investigations, he would be able to defend
only if all organisms were of separate sexes, if every origin
of new individuals were possible only by the mingling of
male and female individuals. But this is by no means
the case. Cmiously enough, Wagner says nothing of
the numerous hermaphrodites which, possessing both the
sexual organs, are capable of self-fructification, and like-
wise nothing of the countless organisms which are not
sexually differentiated.

Now, from the earliest times of the organic history of the
earth, there have existed thousands of organic species
(thousands of which still exist) in which no difference of
sex whatever exists, and, in fact, in which no sexual propa-
gation takes place, and which exclusively reproduce them-

MIGRATION AND HEEMAPHRODITES. 37 1

selves in a non-sexual manner by division, budding, for-
mation of spores, etc. All the great mass of Protista, the
Monera, Amoebae, Myxomycetes, Rhizopoda, etc., in short,
all the lower organisms which we shall have to enumerate
in the domain of Protista, standing midway between the
animal and vegetable kingdoms, propagate themselves
exclusively in a non-sexual manner. And this domain
comprises a class of organisms which is one of the richest
in forms, nay, even in a certain respect the richest of all
in forms, as all possible geometrical fundamental forms are
represented in it. I allude to the wonderful class of the
Rhizopoda, or Ray-streamers, to which the lime-shelled
Acyttaria and the flint-shelled Radiolaria belong. (Com-
pare chapter xvi.)

It is self-evident, therefore, that Wagner's theory is quite
inapplicable to all those non-sexual organisms. Moreover,
the same applies to all those hermaphrodites in which
every individual possesses both male and female organs and
is capable of self-fructification. This is the case, for instance,
in the Flat-worms, flukes, and tapeworms, further in the
important Sack- worms (Tunicates), the invertebrate relatives
of the vertebrate animals, and in very many other organisms
of different groups. Many of these species have arisen by
natural selection, without a " crossing " of the originating
species with its primary form having been possible.

As I have already shown in the eighth chapter, the
origin of the two sexes, and consequently sexual propagation
in general, must be considered as a process which began only
in later periods of the organic history of the earth, being
the result of differentiation or division of labour. The most
ancient terrestrial organisms can have propagated themselves

372 THE HISTOEY OF CEEATION.

only in the simplest non-sexual manner. Even now all
Protista, as well as all the countless forms of cells, which
constitute the body of higher organisms, multiply themselves
only by non-sexual generation. And yet there arise here
" new species " by differentiation in consequence of natural
selection.

But even if we were to take into consideration the animal
and vegetable species with separate sexes, in this case too
we should have to oppose Wagner's chief proposition, that
" the migration of organisms and their formation of colonies
is the necessary condition of natural selection." August
Weismann, in his treatise on the "Influence of Isolation
upon the Formation of Species," ^* has already sufficiently
refuted that proposition, and has shown that even in one
and the same district one bi-sexual species may divide itself
into several species by natural selection. In relation to this
question, I must again, call to mind the great influence
which division of labour, or differentiation, possesses, being
one of the necessary results of natural selection. All
the different kinds of cells constituting the body of the
higher organisms, the nerve cells, muscle cells, gland cells,
etc., all these " good species," these " bonse species " of
elementary organisms, have arisen solely by division of
labour, in consequence of natural selection, although they
not only never were locally isolated, but ever since their
origin have always existed in the closest local relations one
with another. Now, the same reasoning that applies to these
elementary organisms, or " individuals of the first order,"
applies also to the many-celled organisms of a higher order
which only at a later date have arisen as " good species "
from among their fellows.

RECENT AND FOSSIL SPECIES. 373

We are therefore of the same opinion as Darwin and
Wallace, that the migration of organisms and their isolation
in their new home is a very advantageous condition for the
origin of new species; but we cannot admit, as Wagner
asserts, that it is a necessary condition, and that without it
no species can arise. Wagner sets up this opinion, " that
mieration is a necessarv condition for natural selection," as a

Oft/ ■'

special " law of onigration " ; but we consider it sufficiently-
refuted by the above-mentioned facts. We have, moreover,
ah-eady pointed out that in reality the origin of new species
by natural selection is a matheTYiatical and logical necessity
which, without anything else, follows from the simple com-
bination of three great facts. These three fundamental
facts are — the Struggle for Life, the Adaptability, and the
Hereditivity of organisms.

We cannot here enter into detail concerning the numerous
interesting phenomena furnished by the geographical and
topographical distribution of organic species, which are all
wonderfully explained by the theory of selection and
migration. For these I refer to the writings of Darwin,^
Wallace, ^^ and Moritz Wagner, *^ in which the im-
portant doctrine of the limits of clistrihution — seas, rivers,
and mountains — is excellently discussed and illustrated by
numerous examples. Only three other phenomena must
be mentioned here on account of their special importance.
First, the close relation of forms, that is, the striking " family
likeness " existing between the characteristic local forms of
every part of the globe, and their extinct fossil ancestors in
the same part of the globe ; secondly, the no less striking
"family likeness" between the inhabitants of island groups
and those of the neighbouring continent from which iLt

374 THE HISTOEY OF CREATION.

islands were peopled; lastly and thirdly, the peculiar
character presented in general by the flora and fauna of
islands taken as a whole.

All these chorological facts given by Darwin, Wallace,
and Wagner — especially the remarkable phenomena of the
limited local fauna and flora, the relations of insular to conti-
nental inhabitants, the wide distribution of the so-called
"cosmopolitan species," the close relationship of the local
species of the present day with the extinct species of the
same limited territory, the demonstrable radiation of
every species from a single central point of creation — all
these, and all other phenomena furnished to us by the
geographical and the topographical distribution of organisms,
are explained in a simple and thorough manner by the
theory of selection and migration, while without it they are
simply incomprehensible. Consequently, in the whole of
this series of phenomena we find a new and weighty proof
of the truth of the Theory of Descent.

END OF VOL. I,

WORKS OF PROFESSOR ERNST HAECKEL

FREEDOM IN SCID4CE AND TEACHING. Fron

the German of Ernst Haeckel. With a Prefatory Note by T. H.
Huxley, F. R. S. 1 vol., 12mo.

THE EVOLUTION OF MAN. a Popular Exposition of
the Principal Points of Human Ontogeny and Phylogeny. From the
German of Ernst Haeckel, Professor in the University of Jena,
author of " The History of Creation," etc. With numerous Illus-
trations. In two vols., 12mo. Cloth. Price, $5.00.

From, the London Saturday Review.

" In this excellent translation of Professor Haeckel's work, the English reader has
access to the latest doctrines of the Continental school of evolution, in its application to
the history of man. It is in Germany, beyond any other European country, that the
impulse given by Darwin twenty years ago to the theory of evolution has influenced
the whole tenor of philosophical opinion. There may be, and are, diflferences in the
degree to which the doctrine may be held capable of extension into the domain of
mind and morals ; but there is no denying, in scientific circles at least, that as regards
the physical history of organic nature much has been done toward making good a con-
tinuous scheme of being."

THE HISTORY OF CREATION; or, the Development of
the Earth and its Inhabitants by the Action of Natural Causes. A
Popular Exposition of the Doctrine of Evolution in general, and of
that of Darwin, Goethe, and Lamarck in particular. From the Ger-
man of Ernst Haeckel, Professor in the University of Jena. The
translation revised by Professor E. Ray Lankester, M. A., F. R. S.,
Fellow of Exeter College, Oxford. Illustrated with Lithographic
Plates. In 2 vols., 12mo. Cloth, $5.00.

WORKS OF THOMAS H, HUXLEY, LL, D,, F. R. S,

MAN'S PLACE IN NATURE.

1 vol., 12mo. Cloth, $1.25.

ON THE ORIGIN OF SPECIES.

1 vol., 12mo. Cloth, $1.00.

MORE CRITICISMS ON DAR-
WIN, AND ADMINISTRA-
TIVE NIHILISM. 1 vol., 12mo.
Limp cloth, 50 cents.

A MANUAL OF THE ANAT-
OMY OF VERTEBRATED
ANIMALS. lUustrated. 1 vol.,
12mo. Cloth, $2.50.

A MANUAL OF THE ANAT-
OMY OF INVERTEBRAT-

ED ANIMALS. $2.50.

LAY SERMONS, ADDRESSES,
AND REVIEWS. 1 vol., 12mo.
Cloth, $1.75.

CRITIQUES AND ADDRESS-
ES. 12mo. Cloth, $1.50.

AMERICAN ADDRESSES;
w^ith a Lecture on the Study
of Biologry. 12mo. Cloth, $1.25.

PHYSIOGRAPHY: an Intro-
duction to the Study of Na-
ture. With Illustrations and Colored
Plates. 12mo. Cloth, $2.60.

ELEMENTS OF PHYSIOLOGY
AND HYGIENE. By T. H.

HuxLET and W. J. Yotjmans. 1 vol.,
12mo. $1.50.

D. APPLETON & CO., PaBLisHERS, 1, 3, «& 5 Bond Street, N. Y.

EMINENT MODERN SCIENTISTS.

•— ♦-♦ — ►-

HERBERT SPENCER'S WORKS. . U vols., 12mo. Cloth, $25.25.

FiKST Principles.. $2

00
00
00

Principles of Biology. 2 vols... 4
Principles of Psychology. 2 vols. 4
Principles of Sociology. Vol. I.

Parts I., II., and III 2 00

Ceremonial Institutions. Being'
Part IV. of the Principlee of Soci-
ology 1 25

Data of Ethics 1 25

Study of Sociology. (International

Scientific Series) $1 50

Education 1 25

Discussions in Science, Philoso-
phy, AND Morals 2 00

Universal' Progress 2 00

Essays : Moral, Political, and -lEs-

thetic 2 00

Social Statics 2 00

Philosophy of Style. 12mo. Flexible cloth, 50 cents.

Descriptive Sociology. To Subscribers, for the whole work, per part, $3.50; single
part. 14.00. Published in folio, with Tables. Six Parts now ready, namely; 1.
English; 2. Ancient Americans; 3. Negritto and Malayo-Polynesian Eaces; 4.
African Races ; 5. Asiatic Races ; 6. North and South American Races.

CHARLES DARWIN'S WORKS. 11 vols., 12mo. Cloth, $24.00.

Origin of Species $2 00

DcISCBnt of Man 3 00

Journal of Researches 2 00

Emotional Expression 8 50

Animals and Plants under Do-

MBSTICATION. 2 VOlS 5 00

Insectitoeous Plants $2 00

Climbing Plants 1 25

Orchids fertilized by Insects... 1 75
Fertilization in the Vegetable

Kingdom 2 00

Forms of Flowers 1 50

THOMAS H. HUXLEY'S WORKS.

Man's Place in Nature |1 25

On the Origin of Species 1 00

More Criticisms on Darwin, and

Administrative Nihilism 50

A Manual of the Anatomy of

Vertebrated Animals. Illus'd. . 2 50
A Manual of the Anatomy of In-

VERTEBRATED Animals, lllus'd.. 2 50
Lay Sermons, Addresses, and Re-
views 1 75

n vols., 12mo. Cloth, $18.00.

Critiques and Addresses $1 50

American Addresses 1 25

Physiography 2 50

Elements of Physiology and Hy-
giene. By T. H. Huxley and W.

J. Youmans 1 50

The Crayfish: An Introduction to
Zoology. (International Scientifle.^
Series) 1 75

JOHN TYNDALL'S WORKS. 10 vols., 12mo. Cloth, $19.75.

Heat as a Mode of Motion $2 00

On Sound 2 00

Fragments of Science 2 50

Light and Electricity 1 25

Lessons in Electricity 1 00

Hours of Exercise in the Alp8.|2 00

Faeaday as a Discoverer 1 00

On Forms of Watee 1 50

Radiant Heat. 5 00

Six Lectuebs on Light 1 50

Banquet at Delmonico's, paper, 50 centa ; Belfast Address, paper, 50 cents.

D. APPLETON & CO., Pcbli8hf.es, 1, 8, & 5 Bond Street, New Tobk.

/

W^

.ra^'

\:r^^

Mn

w

/A^/.

4(m^

N'>

//iiti!